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@vargentum/react-hotkeys
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2.0.0-pre6 • Public • Published


React HotKeys

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A declarative library for handling hotkeys and focus areas in React applications.

🚨 🚨 Warning: This Readme is for the latest pre-release. The documentation for the latest stable release is available here. 🚨 🚨

Upgrading from 1.*.* ?

See the upgrade notes.

Feature Overview

Basic Usage

Define a key map

import { HotKeys } from "react-hotkeys";
import MyNode from "./MyNode";

const keyMap = {
  SNAP_LEFT: "command+left",
  DELETE_NODE: ["del", "backspace"]
};

const App = () => {
  return (
    <HotKeys keyMap={keyMap}>
      <div>
        <MyNode />
        <MyNode />
      </div>
    </HotKeys>
  );
};

export default App;

Define handlers

import { HotKeys } from "react-hotkeys";

const MyNode = () => {
  const handlers = {
    DELETE_NODE: this.deleteNode
  };

  return <HotKeys handlers={handlers}>Node contents</HotKeys>;
};

export default MyNode;

Contents

Licenses

react-hotkeys is released under the ISC License.

However, please note: the source code found in the lib/vendor directory is under the MIT License - please see the license file for each directory for more information.

Install

CommonJS & ES6 Modules

react-hotkeys is available as a CommonJS or a ES6 Modules through npm or yarn. It uses NODE_ENV to determine whether to export the development or production build in your library or application.

It is expected you will use a bundling tool like Webpack or Uglify to remove the version of the bundle you are not using with each version of your application's code, to keep the library size to a minimum.

The latest pre-release

npm
npm install react-hotkeys@next --save
yarn
yarn add react-hotkeys@next

Latest stable release

npm
npm install react-hotkeys --save
yarn
yarn add react-hotkeys

UMD

react-hotkeys as a UMD module is available on your CDN of choice.

Change 1.0.1 for the version that you would like to use.

Development build

<script crossorigin src="https://cdn.jsdelivr.net/npm/react-hotkeys@1.0.1/umd/react-hotkeys.js"></script>

<script crossorigin src="https://unpkg.com/react-hotkeys@1.0.1/umd/react-hotkeys.js"></script>

Minified production build

<script crossorigin src="https://cdn.jsdelivr.net/npm/react-hotkeys@1.0.1/umd/react-hotkeys.min.js"></script>

<script crossorigin src="https://unpkg.com/react-hotkeys@1.0.1/umd/react-hotkeys.min.js"></script>

Bower

Bower support was removed in v1.0.0, but those who already rely on earlier versions of react-hotkeys through Bower can continue to do so using the following command:

bower install react-hotkeys@0.10.0

The Bower version of the package will not be supported going forward (including fixing any outstanding issues).

Defining key maps

react-hotkeys uses key maps to decouple defining keyboard shortcuts from the functions they call. This allows hot keys and handler functions to be defined and maintained independent of one another.

When a user presses the corresponding combination or sequence of keys, it is said they match the hot keys, which causes an action to be triggered. react-hotkeys may then resolve an appropriate handler function to handle the action.

Key maps are Plain Old JavaScript Objects, where the keys are the action names and the values are usually a Mousetrap-supported or Browser Key Values sequence string (but can also be an array or an object) that must be matched in order to trigger the action.

const keyMap = {
  deleteNode: "del",
  moveUp: "up"
};

Key Combinations vs Sequences

Every hotkey or sequence string is parsed and treated as a sequence of key combinations. The simplest case is a sequence of 1 key combination, consisting of 1 key: e.g. 'a' or 'shift'.

// Key sequence with a combination of a single key
'4'

// Special single key sequence (ie. shift is handled automagically)
'?'

// Sequence of a single combination with multiple keys (keys must be pressed at the same time)
'command+shift+k'

// Sequence of multiple combinations (keys must be pressed and released one after another)
'up down left right'

Full Reference

Please refer to Mousetrap's documentation or Browser Key Values for an exhaustive list of supported shortcuts and sequences.

Alternative Hotkeys

You can specify multiple alternative key sequences (they will trigger the same action) using arrays:

const keyMap = {
  DELETE_NODE: ["del", "backspace"],
  MOVE_UP: ["up", "w"]
};

Specifying key events (keydown, keypress, keyup)

By default, react-hotkeys will match hotkey sequences on the keydown event (or, more precisely: on the keydown event of the last key to complete the last combination in a sequence).

If you want to trigger a single action on a different key event, you can use the object syntax and the action attribute to explicitly set which key event you wish to bind to:

const keyMap = {
  CONTRACT: "alt+down",
  COMMAND_DOWN: { sequence: "command", action: "keydown" }
};

If you want to change the default key event for all hotkeys, you can use the defaultKeyEvent option of the configuration API.

The full list of valid key events is: keypress, keydown, and keyup.

Deciding which key map syntax to use

As a general rule, you should use the syntax that is the most brief, but still allows you to express the configuration you want.

Question Yes No
Need to define alternative key sequences to trigger the same action? Use an array of strings or objects. Use a string or object.
Need to explicitly define the key event to bind to (or some other additional option)? Use an object. Use a string.

Defining Handlers

Key maps trigger actions when they match a key sequence. Handlers are the functions that react-hotkeys calls to handle those actions.

Handlers may be defined in the same <HotKeys /> component as the key map:

import { HotKeys } from "react-hotkeys";

const keyMap = {
  MOVE_UP: "up"
};

const handlers = {
  MOVE_UP: event => console.log("Move up hotkey called!")
};

<HotKeys keyMap={keyMap} handlers={handlers}>
  <input />
</HotKeys>;

Or they may be defined in any descendant of the <HotKeys /> component that defines the key map:

import { HotKeys } from "react-hotkeys";

const keyMap = {
  MOVE_UP: "up"
};

const handlers = {
  MOVE_UP: event => console.log("Move up hotkey called!")
};

<HotKeys keyMap={keyMap}>
  <div>
    <HotKeys handlers={handlers}>
      <input />
    </HotKeys>
  </div>

  <div>
    <input />
  </div>
</HotKeys>;

DEPRECATED: Hard Sequence Handlers

Handlers associated to actions with names that are valid key sequence strings implicitly define actions that are matched by the corresponding key sequence. This means you do not have to define the key maps in order for these handlers to "just work".

This functionality is not advised and exists mainly for backwards compatibility. It is generally advisable to explicitly define an action in a key map rather than rely on this behaviour.

To use hard sequence handlers, you must first enable them using the enableHardSequences configuration option.

/**
 * If no named 'up' action has been defined in a key map and it is a valid
 * key sequence, react-hotkeys assumes it's a hard sequence handler and
 * implicitly defines an action for it
 */

const handlers = {
  up: event => console.log("up key called")
};

Interaction with React

Rather than re-invent the wheel, react-hotkeys piggy-backs of the React SyntheticEvent and event propagation, so all of the normal React behaviour that you expect still applies.

  • Key events propagate up from a source or target towards the root of the application.
  • If an event has stopPropagation() called on it, it will not be seen by components higher up in the render tree.

HotKeys components

<HotKeys> components listen only to key events that happen when one of their DOM-mounted descendents are in focus (<div/>, <span/>, <input/>, etc). This emulates (and re-uses) the behaviour of the browser and React's SyntheticEvent propagation.

This is the default type of <HotKeys /> component, and should normally be your first choice for efficiency and clarity (the user generally expects keyboard input to affect the focused element in the browser).

How action handlers are resolved

If one of the DOM-mounted descendents of an <HotKeys> component are in focus (and it is listening to key events) AND those key events match a hot key in the component's key map, then the corresponding action is triggered.

react-hotkeys starts at the <HotKeys /> component closest to the event's target (the element that was in focus when the key was pressed) and works its way up through the component tree of focused <HotKeys /> components, looking for a matching handler for the action. The handler closest to the event target AND a descendant of the <HotKeys /> component that defines the action (or the component itself), is the one that is called.

That is:

  • Unless one of the DOM-mounted descendents of a <HotKeys> component is in focus, the component's actions are not matched
  • Unless a <HotKeys> component is nested within the <HotKeys /> component that defines the action (or is the same <HotKeys /> component), its handler is not called
  • If a <HotKeys /> component closer to the event target has defined a handler for the same action, a <HotKeys /> component's handler won't be called (the closer component's handler will)

A more exhaustive enumeration of react-hotkeys behaviour can be found by reviewing the test suite.

HotKeys component API

The HotKeys component provides a declarative and native JSX syntax that is best for succinctly declaring hotkeys in a way that best maintains separation and encapsulation with regards to the rest of your code base.

However, it does require that its children be wrapped in a DOM-mounted node, which can break styling and add extra levels to your render tree.

<HotKeys
  /**
   * An object that defines actions as keys and key sequences as values
   * (using either a string, array or object).
   *
   * Actions defined in one HotKeys component are available to be handled
   * in an descendent HotKeys component.
   *
   * Optional.
   */
  keyMap={ {} }

  /**
   * An object that defines handler functions as values, and the actions
   * that they handle as keys.
   *
   * Optional.
   */
  handlers={ {} }

  /**
   * The type of DOM-mountable component that should be used to wrap
   * the component's children.
   */
  component={ 'div' }

  /**
   * tabindex value to pass to DOM-mountable component wrapping children
   */
  tabIndex={-1}

  /**
   * Whether the keyMap or handlers are permitted to change after the
   * component mounts. If false, changes to the keyMap and handlers
   * props will be ignored
   *
   * Optional.
   */
  allowChanges={false}

  /**
   * A ref to add to the underlying DOM-mountable node. Pass a function
   * to get a reference to the node, so you can call .focus() on it
   */
  innerRef: {undefined}
  >

  /**
   * Wraps all children in a DOM-mountable component
   */
   { children }

</HotKeys>

withHotKeys HoC API

The HotKeys component API is generally recommended, but if wrapping your component in a DOM-mountable node is not acceptable, or you need more control over how the react-hotkeys props are applied, then the withHotKeys() HoC is available.

Simple use-case

The simplest use-case of withHotKeys() is to simply pass it your component class as the first argument. What is returned is a new component that will accept all of the same props as a <HotKey> component, so you can specify key maps and handlers at render time, for example.

The component you wrap must take responsibility for passing the hotKeys props to a DOM-mountable element. If you fail to do this, key events will not be detected when a descendant of the component is in focus.

import { withHotKeys } from "react-hotkeys";

class MyComponent extends Component {
  render() {
    /**
     * Must unwrap hotKeys prop and pass its values to a DOM-mountable
     * element (like the div below).
     */
    const { hotKeys, ...remainingProps } = this.props;

    return (
      <div {...{ ...hotKeys, ...remainingProps }}>
        <span>My HotKeys are effective here</span>

        {this.props.children}
      </div>
    );
  }
}

const MyHotKeysComponent = withHotKeys(MyComponent);

const keyMap = {
  TEST: "t"
};

const handlers = {
  TEST: () => console.log("Test")
};

<MyHotKeysComponent keyMap={keyMap} handlers={handlers}>
  <div>You can press 't' to log to the console.</div>
</MyHotKeysComponent>;

Pre-defining default prop values

You can use the second argument of withHotKeys to specify default values for any props you would normally pass to <HotKeys />. This means you do not have to specify them at render-time.

If you do provide prop values when you render the component, these will be merged with (and override) those defined in the second argument of withHotKeys.

import { withHotKeys } from "react-hotkeys";

class MyComponent extends Component {
  render() {
    /**
     * Must unwrap hotKeys prop and pass its values to a DOM-mountable
     * element (like the div below).
     */
    const { hotKeys, ...remainingProps } = this.props;

    return (
      <div {...{ ...hotKeys, ...remainingProps }}>
        <span>My HotKeys are effective here</span>

        {this.props.children}
      </div>
    );
  }
}

const keyMap = {
  TEST: "t"
};

const handlers = {
  TEST: () => console.log("Test")
};

const MyHotKeysComponent = withHotKeys(MyComponent, { keyMap, handlers });

/**
 * Render without having to specify prop values
 */
<MyHotKeysComponent>
  <div>You can press 't' to log to the console.</div>
</MyHotKeysComponent>;

GlobalHotKeys component

<GlobalHotKeys> components match key events that occur anywhere in the document (even when no part of your React application is in focus).

const keyMap = { SHOW_ALL_HOTKEYS: "shift+?" };
const handlers = { SHOW_ALL_HOTKEYS: this.showHotKeysDialog };

<GlobalHotKeys keyMap={keyMap} handlers={handlers} />;

<GlobalHotKeys> generally have no need for children, so should use a self-closing tag (as shown above). The only exception is when you are nesting other <GlobalHotKeys> components somewhere in the descendents (these are mounted before their parents, and so are generally matched first).

How actions and handlers are resolved

Regardless of where <GlobalHotKeys> components appear in the render tree, they are matched with key events after the event has finished propagating through the React app (if the event originated in the React at all). This means if your React app is in focus and it handles a key event, it will be ignored by the <GlobalHotKeys> components.

The order used for resolving actions and handlers amongst <GlobalHotKeys> components, is the order in which they mounted (those mounted first, are given the chance to handle an action first). When a <GlobalHotKeys> component is unmounted, it is removed from consideration. This can get less deterministic over the course of a long session using a React app as components mount and unmount, so it is best to define actions and handlers that are globally unique.

It is recommended to use <HotKeys> components whenever possible for better performance and reliability.

You can use the autofocus attributes or programmatically manage focus to automatically focus your React app so the user doesn't have to select it in order for hot keys to take effect. It is common practice to place a <HotKeys> component towards the top of your application to match hot keys across your entire React application.

GlobalHotKeys component API

The GlobalHotKeys component provides a declarative and native JSX syntax for defining hotkeys that are applicable beyond you React application.

<GlobalHotKeys
  /**
   * An object that defines actions as keys and key sequences as values
   * (using either a string, array or object).
   *
   * Actions defined in one HotKeys component are available to be handled
   * in an descendent HotKeys component.
   *
   * Optional.
   */
  keyMap={{}}
  /**
   * An object that defines handler functions as values, and the actions
   * that they handle as keys.
   *
   * Optional.
   */
  handlers={{}}
  /**
   * Whether the keyMap or handlers are permitted to change after the
   * component mounts. If false, changes to the keyMap and handlers
   * props will be ignored
   *
   * Optional.
   */
  allowChanges={false}
>
  /** * Wraps all children in a DOM-mountable component */
  {children}
</GlobalHotKeys>

Displaying a list of available hot keys

react-hotkeys provides the getApplicationKeyMap() function for getting a mapping of all actions and key sequences that have been defined by components that are currently mounted.

They are returned as an object, with the action names as keys (it is up to you to decide how to translate them to be displayed) and arrays of key sequences that trigger them, as keys.

Below is how the example application renders a dialog of all available hot keys:

import { getApplicationKeyMap } from 'react-hotkeys';

// ...

renderDialog() {
    if (this.state.showDialog) {
      const keyMap = getApplicationKeyMap();

      return (
        <div style={styles.DIALOG}>
          <h2>
            Keyboard shortcuts
          </h2>

          <table>
            <tbody>
            { Object.keys(keyMap).map((actionName) => (
              <tr key={actionName}>
                <td style={styles.KEYMAP_TABLE_CELL}>
                  { actionName.replace('_', ' ') }
                </td>
                <td style={styles.KEYMAP_TABLE_CELL}>
                  { keyMap[actionName].map((keySequence) => <span key={keySequence}>{keySequence}</span>) }
                </td>
              </tr>
            )) }
            </tbody>
          </table>
        </div>
      );
    }
  }

Allowing hotkeys and handlers props to change

For performance reasons, by default react-hotkeys takes the keyMap and handlers prop values when <HotKeys> components are focused and when <GlobalHotKeys> components are mounted. It ignores all subsequent updates to their values when these props change.

If you need the ability to change them while <HotKeys> are still in focus, or while <GlobalHotKeys> are still mounted, then you can pass the allowChanges prop, permitting this behaviour for the particular component.

If you need to do this for all your <HotKeys> and <GlobalHotKeys> components, you can use the ignoreKeymapAndHandlerChangesByDefault option for the Configuration API. This should normally never be done, as it can have significant performance implications.

Ignoring events

By default, all key events that originate from <input>, <select> or <textarea>, or have a isContentEditable attribute of true are ignored by react-hotkeys.

If this is not what you want for your application, you can modify the list of tags using the ignoreTags configuration option or if you need additional control, you can specify a brand new function using the ignoreEventsCondition configuration option.

If you want an exception to the global ignore policy for a particular part of your app, then you can use the ObserveKeys component.

What it actually means to ignore an event

When a keyboard event occurs, two things happen:

  • It's added to the record of the keys currently pressed (the current combination) and those were recently pressed (the current key sequence)
  • It's compared against the list of hotkeys you have defined

When you ignore an event, if it's a keydown event (a new key is being pressed), it is not added to the key history and no attempt is made to match it against your hotkeys. If it's a keypress or a keyup event and the key already exists in the history, the event is recorded (the key is being released) but no attempt is made to find a corresponding hotkey.

This effectively means, no new ignored keys are recorded and any keys that are already pressed are recorded as being released so they don't bleed into subsequent key combinations.

IgnoreKeys component

You only need this component if you want to add extra key events to ignore, that are not already matched by ignoreEventsCondition().

If you want react-hotkeys to ignore key events coming from a particular area of your app when it is in focus, you can use the <IgnoreKeys/> component:

import { IgnoreKeys } from "react-hotkeys";

<IgnoreKeys>
  /** * Children that, when in focus, should have its key events ignored by *
  react hotkeys */
</IgnoreKeys>;

IgnoreKeys component API

By default, <IgnoreKeys /> will ignore all key events, but you can customize this behaviour by providing a whitelist or blacklist of events to ignore:

<IgnoreKeys
    /**
     * The whitelist of keys that keyevents should be ignored. i.e. if you place
     * a key in this list, all events related to it will be ignored by react
     * hotkeys.
     *
     * Accepts a string or an array of strings.
     */
      only: { [] }

     /**
      * The blacklist of keys that keyevents should be not ignored. i.e.
      * if you place a key in this list, all events related to it will be
      * still be observed by react hotkeys
      */
     except: { [] }
    >

    /**
     * Children that, when in focus, should have its key events ignored by
     * react hotkeys
     */

     { children }

</IgnoreKeys>

withHotKeysIgnore HoC API

Similar to the <HotKeys>'s withHotKeys() function, there is a withIgnoreKeys() function for achieving the <IgnoreKeys> functionality, without the need for rendering a surrounding DOM-mountable element.

import { withHotKeysIgnore } from "react-hotkeys";

class MyComponent extends Component {
  render() {
    /**
     * Must unwrap hotKeys prop and pass its values to a DOM-mountable
     * element (like the div below).
     */
    const { hotKeys, ...remainingProps } = this.props;

    return (
      <div {...{ ...hotKeys, ...remainingProps }}>
        <span>HotKeys ignores key events from here</span>

        {this.props.children}
      </div>
    );
  }
}

const MyHotKeysComponent = withHotKeysIgnore(MyComponent);

<MyHotKeysComponent except={"Escape"}>
  <div>All key events except the 'Escape' key are ignored here</div>
</MyHotKeysComponent>;

withIgnoreKeys() also accepts a second argument that becomes the default props of the component it returns:

import { withHotKeysIgnore } from "react-hotkeys";

class MyComponent extends Component {
  render() {
    /**
     * Must unwrap hotKeys prop and pass its values to a DOM-mountable
     * element (like the div below).
     */
    const { hotKeys, ...remainingProps } = this.props;

    return (
      <div {...{ ...hotKeys, ...remainingProps }}>
        <span>HotKeys ignores key events from here</span>

        {this.props.children}
      </div>
    );
  }
}

const MyHotKeysComponent = withHotKeysIgnore(MyComponent, { except: "Escape" });

<MyHotKeysComponent>
  <div>All key events except the 'Escape' key are ignored here</div>
</MyHotKeysComponent>;

ObserveKeys component

You only need this component if you want to add exceptions to the key events that are matched by ignoreEventsCondition() (i.e. you want to observe key events, even though they are globally ignored by default).

If you want react-hotkeys to always observe key events coming from a particular area of your app when it is in focus (despite the global ignoreEventsCondition), you can use the <ObserveKeys/> component:

import {ObserveKeys} from 'react-hotkeys';

<ObserveKeys>
    /**
     * Children that, when in focus, should have its key events always
     * observed by react hotkeys
     */
</ObserveKeys>

ObserveKeys component API

By default, <ObserveKeys /> will force all key events to be observed, but you can customize this behaviour by providing a whitelist or blacklist of events to ignore:

<ObserveKeys
    /**
     * The whitelist of keys that keyevents should be forced to be observed.
     * i.e. if you place a key in this list, all events related to it will be
     * observed by react hotkeys - even if it's ignored by the
     * ignoreEventsCondition.
     *
     * Accepts a string or an array of strings.
     */
      only: { [] }

     /**
      * The blacklist of keys that keyevents should be forced to be observed.
      * i.e. if you place a key in this list, all events related to it will be
      * still be ignored by react hotkeys if they match ignoreEventsCondition
      */
     except: { [] }
    >

    /**
     * Children that, when in focus, should have its key events observed by
     * react hotkeys - even if they match ignoreEventsCondition
     */

     { children }

</ObserveKeys>

withObserveKeys HoC API

Similar to the <HotKeys>'s withHotKeys() function, there is a withObserveKeys() function for achieving the <ObserveKeys> functionality, without the need for rendering a surrounding DOM-mountable element.

import {withObserveKeys} from 'react-hotkeys';

class MyComponent extends Component {
  render() {
    /**
     * Must unwrap hotKeys prop and pass its values to a DOM-mountable
     * element (like the div below).
     */
    const {hotKeys, ...remainingProps} = this.props;

    return (
      <div { ... { ...hotKeys, ...remainingProps } } >
        <span>HotKeys always observes key events from here</span>

       { this.props.children }
      </div>
    )
  }
}

const MyHotKeysComponent = withObserveKeys(MyComponent);

<MyHotKeysComponent except={ 'Escape' }>
  <div>
    All key events except the 'Escape' key are observed here
  </div>
</MyHotKeysComponent>

withObserveKeys() also accepts a second argument that becomes the default props of the component it returns:

import {withObserveKeys} from 'react-hotkeys';

class MyComponent extends Component {
  render() {
    /**
     * Must unwrap hotKeys prop and pass its values to a DOM-mountable
     * element (like the div below).
     */
    const {hotKeys, ...remainingProps} = this.props;

    return (
      <div { ... { ...hotKeys, ...remainingProps } } >
        <span>HotKeys observes key events from here</span>

       { this.props.children }
      </div>
    )
  }
}

const MyHotKeysComponent = withObserveKeys(MyComponent, { except: 'Escape' });

<MyHotKeysComponent>
  <div>
    All key events that match the ignoreEventsCondition are still observed here, except the 'Escape' key
  </div>
</MyHotKeysComponent>

Configuration

The default behaviour across all <HotKeys> components is configured using the configure method.

configure() should be called as your app is initialising and before the first time you mount a <HotKeys> component anywhere your app.

The following options are available (default values are shown):

import {configure} from 'react-hotkeys';

configure({
  /**
   * The level of logging of its own behaviour React HotKeys should perform.
   */
  logLevel: 'warn',

  /**
   * Default key event key maps are bound to (keydown|keypress|keyup)
   */
  defaultKeyEvent: 'keydown',

  /**
   * The default component type to wrap HotKey components' children in, to provide
   * the required focus and keyboard event listening for HotKeys to function
   */
  defaultComponent: 'div',

  /**
   * The default tabIndex value passed to the wrapping component used to contain
   * HotKey components' children. -1 skips focusing the element when tabbing through
   * the DOM, but allows focusing programmatically.
   */
  defaultTabIndex: '-1',

  /**
   * The HTML tags that React HotKeys should ignore key events from. This only works
   * if you are using the default ignoreEventsCondition function.
   * @type {String[]}
   */
  ignoreTags: ['input', 'select', 'textarea'],

  /**
   * The function used to determine whether a key event should be ignored by React
   * Hotkeys. By default, keyboard events originating elements with a tag name in
   * ignoreTags, or a isContentEditable property of true, are ignored.
   *
   * @type {Function<KeyboardEvent>}
   */
  ignoreEventsCondition: function,

/**
   * Whether to allow hard sequences, or the binding of handlers to actions
   * that have names that are valid key sequences, which implicitly define
   * actions that are triggered by that key sequence
   */
  enableHardSequences: false,

  /**
   * Whether to ignore changes to keyMap and handlers props by default
   * (this reduces a significant amount of unnecessarily resetting
   * internal state)
   * @type {Boolean}
   */
  ignoreKeymapAndHandlerChangesByDefault: true,

  /**
   * Whether React HotKeys should simulate keypress events for the keys that do not
   * natively emit them.
   * @type {Boolean}
   */
  simulateMissingKeyPressEvents: true,

  /**
   * Whether to call stopPropagation() on events after they are
   * handled (preventing the event from bubbling up any further, both within
   * React Hotkeys and any other event listeners bound in React).
   *
   * This does not affect the behaviour of React Hotkeys, but rather what
   * happens to the event once React Hotkeys is done with it (whether it's
   * allowed to propagate any further through the Render tree).
   */
   stopEventPropagationAfterHandling: true,

  /**
   * Whether to call stopPropagation() on events after they are
   * ignored (preventing the event from bubbling up any further, both within
   * React Hotkeys and any other event listeners bound in React).
   *
   * This does not affect the behaviour of React Hotkeys, but rather what
   * happens to the event once React Hotkeys is done with it (whether it's
   * allowed to propagate any further through the Render tree).
   */
   stopEventPropagationAfterIgnoring: true,
});

Logging

react-hotkeys provides comprehensive logging of all of its internal behaviour and allows setting one of 6 log levels.

The default level is warn, which provides warnings and errors only, and is generally sufficient for most usage. However, if you are troubleshooting an issue or reporting a bug, you should increase the log level to debug or verbose to see what is going on, and be able to communicate it concisely.

You can set the logging level using the logLevel configuration option.

For performance reasons, only some of the log levels are available in the production build. You will need to use the development build to get the full log output.

Log Level Severity Description Available in Dev Available in Prod
verbose (highest) debug + internal data representations Yes No
debug info + event propagation info Yes No
info warn + general info Yes No
warn (default) error + warnings Yes Yes
error Errors only (ignore warnings) Yes Yes
none (lowest) Log nothing Yes Yes

Logs appear in the developer console of the browser.

Each line is prefixed with (where applicable):

  • The focus tree id
  • The component id
  • The event id

Each id is also given a coloured emoticon, to make it easy to visually trace the propagation of particular events through multiple components.

Optimizations

react-hotkeys uses a lot of optimizations to help keep it as performant as possible (both in terms of time and memory). It can be helpful to be aware of some of these measures if you are seeing unexpected behaviour:

Code optimizations

  • If an event is handled by an earlier handler, it is ignored by an further components (this is really a design decision, rather than an optimization, but it helps).
  • By default, stopPropagation() is called on all key events once react-hotkeys has handled them. This can be disabled via the stopEventPropagationAfterHandling and stopEventPropagationAfterIgnoring configuration options.
  • Events are ignored unless an action exists that is bound to that particular event type (keydown, keypress, keyup)
  • Events are processed at each level, as they propagate up the React render tree. If a action is triggered by a leaf node, react-hotkeys stops there (and does not build the full application's mappings of key sequences and handlers)
  • Changes to keyMaps and handlers are ignored unless you explicitly opt-in to the behaviour of resetting them each time their prop value changes.
  • Key histories longer than the longest registered key sequence are discarded.
  • The mapping between an action's key sequences and handlers is built "on-the-fly", so unless a particular action is triggered, react-hotkeys doesn't do the work of finding its corresponding handler.
  • Global event listeners are only bound to document when a global hotkey is defined (and are removed when the last one is unmounted).

Production optimizations

  • The production build strips out all comments and logging statements below a level of warning, before undergoing minification using Uglify.
  • An es6 version is also available, that allows for tree-shaking in compatible build setups.

Managing focus in the browser

Focusable elements

HTML5 allows any element with a tabindex attribute to receive focus.

If you wish to support HTML4 you are limited to the following focusable elements:

  • <a>
  • <area>
  • <button>
  • <input>
  • <object>
  • <select>
  • <textarea>

Tab Index

If no elements have a tabindex in a HTML document, the browser will tab between focusable elements in the order that they appear in the DOM.

If there are elements with tabindex values greater than zero, they are iterated over first, according their tabindex value (from smallest to largest). Then the browser tabs over the focusable elements with a 0 or unspecified tabindex in the order that they appear in the DOM.

If any element is given a negative tabindex, it will be skipped when a user tabs through the document. However, a user may still click or touch on that element and it can be focused programmatically (see below).

By default, <HotKeys> render its children inside an element with a tabindex of -1. You can change this by passing a tabIndex prop to <HotKeys> or you can change the default tabindex value for all components using thedefaultTabIndex` option for the Configuration API.

Autofocus

HTML5 supports a boolean autofocus attribute on the following input elements:

  • <button>
  • <input>
  • <select>
  • <textarea>

It can be used to automatically focus parts of your React application, without the need to programmatically manage focus.

Only one element in the document should have this attribute at any one time (the last element to mount with the attribute will take effect).

Programmatically manage focus

To programmatically focus a DOM element, it must meet two requirements:

You can get a reference to an element using React's ref property:

class MyComponent extends Component {
  componentDidUpdate(prevProps) {
    if (!prevProps.isFocused && this.props.isFocused) {
      this._container.focus();
    }
  }

  render() {
    return <div ref={c => (this._container = c)}>My focusable content</div>;
  }
}

To get a reference to the DOM-mountable node used as a wrapper by <HotKeys />, use the innerRef prop:

class MyComponent extends Component {
    componentDidMount() {
        this._container.focus();
    }

    render() {
        return (
            <HotKeys innerRef={ (c) => this._container = c } >
                My focusable content
            </div>
        )
    }

}

Get the element currently in focus

You can retrieve the element that is currently focused using the following:

document.activeElement;

Preventing default browser behaviour

If you find that you want to bind to a key sequence that is already used by the browser, you can prevent the default behaviour by calling the preventDefault method on the event object:

event.preventDefault();

It's generally not advised to do this, as it likely violates the Principle of Least Surprise.

Troubleshooting & Gotchas

Hotkeys is wrapping my components in a div that is breaking my styling

You have 3 options:

  1. Use the component prop to specify a span or some other alternative DOM-mountable component to wrap your component in, each time you render a component you don't want to wrap in a div element.
  2. Use the defaultComponent configuration option to specify a span or some other alternative DOM-mountable component to wrap all <HotKeys> children in.
  3. Use the withHotKeys HoC API to avoid rendering a wrapping component at all.

Other keyboard event listeners are no longer being triggered

For improved performance, by default react-hotkeys calls stopPropagation() on all events that it handles. You can change this using the stopEventPropagationAfterHandling and stopEventPropagationAfterIgnoring configuration options.

Actions aren't being triggered when using withHotKeys

Check that you are correctly passing the hotKeys props to a DOM-mountable component.

Actions aren't being triggered for HotKeys

Make sure you are focusing a descendant of the <HotKeys> component before you press the keys.

Check that the <HotKeys> component that defines the handler is also an ancestor of the focused component, and is above (or is) the component that defines the handlers.

Also make sure your React application is not calling stopPropagation() on the key events before they reach the <HotKeys> component that defines the keyMap.

Finally, make sure your key event are not coming from one of the tags ignored by react-hotkeys.

Blue border appears around children of HotKeys

react-hotkeys adds a <div /> around its children with a tabindex="-1" to allow them to be programmatically focused. This can result in browsers rendering a blue outline around them to visually indicate that they are the elements in the document that is currently in focus.

This can be disabled using CSS similar to the following:

div[tabindex="-1"]:focus {
  outline: 0;
}

Support

Please use Gitter to ask any questions you may have regarding how to use react-hotkeys.

If you believe you have found a bug or have a feature request, please open an issue.

Stability & Maintenance

react-hotkeys is considered stable and already being widely used (most notably Lystable and Whatsapp).

Contribute, please!

If you're interested in helping out with the maintenance of react-hotkeys, make yourself known on Gitter, open an issue or create a pull request.

All contributions are welcome and greatly appreciated - from contributors of all levels of experience.

Collaboration is loosely being coordinated across Gitter and Projects.

Using GitHub Issues

  • Use the search feature to check for an existing issue
  • Include as much information as possible and provide any relevant resources (Eg. screenshots)
  • For bug reports ensure you have a reproducible test case
    • A pull request with a breaking test would be super preferable here but isn't required

Submitting a Pull Request

  • Squash commits
  • Lint your code with eslint (config provided)
  • Include relevant test updates/additions

Build notes

react-hotkeys uses a mixture of build tools to create each of the development and production bundles, which can be confusing to navigate and understand.

Build scripts

All build commands are included in the package.json:

Command Description
yarn prepublish Build all bundles using babel and rollup
yarn build-cjs Build the development and production CommonJS bundles using babel and rollup, respectively
yarn build-es Build the development and production ES6 bundles using babel and rollup, respectively
yarn build-umd Build the development and production UMD bundles using rollup
yarn build-development Build the development CommonJS bundle using babel
yarn build-es-development Build the development ES6 bundle using babel
yarn build-umd-development Build the development ES6 bundle using rollup
yarn build-production Build the production CommonJS bundle using rollup
yarn build-es-production Build the production ES6 bundle using rollup
yarn build-umd-production Build the production ES6 bundle using rollup

Development builds

Bundle Transpiled with Modularized with Output
CommonJS Babel Babel /cjs/index.js
UMD Babel Rollup /umd/index.js
ES6 Babel Babel /es/index.js

Production builds

Bundle Transpiled with Optimized with Minified with Output
CommonJS Babel Rollup Uglify cjs/react-hotkeys.production.min.js
UMD Babel Rollup Uglify /umd/react-hotkeys.min.js
ES6 Babel Rollup Babel-minify /es/react-hotkeys.production.min.js

Build configuration

To understand the configuration for any one build, you need to consult 3 places:

  • The CLI arguments used in the scripts of package.json
  • The .babelrc file (match the env to the BABEL_ENV value set in scripts above)
  • The rollup.configs.js (if applicable)

Authorship

All credit, and many thanks, goes to Chris Pearce for the inception of react-hotkeys and all versions before 1.0.0.

Readme

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Install

npm i @vargentum/react-hotkeys

Repository

github.com/greena13/react-hotkeys

Homepage

github.com/greena13/react-hotkeys

Weekly Downloads

19

Version

2.0.0-pre6

License

ISC

Unpacked Size

978 kB

Total Files

150

Last publish

Collaborators

  • vargentum
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