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reactlink-immutable

ReactLink-Immutable Version

A React mixin that provides two-way data binding for components using ImmutableJS data structures as properties of this.state.

Huh? ReactLink?

Ok, let's back up a little bit. React provides a method, known as ReactLink, to update this.state on a component whenever the value of an <input> field changes. This method is exposed by the convenient mixin React.addons.LinkedStateMixin, which essentially just binds the onChange event handler of the <input> field to the this.setState() function.

This is great, especially when creating a component with multiple input fields, but it starts to fall apart if you want to use deeply-nested objects inside this.state of your component.

In that case, Facebook recomments using their ImmutableJS library to create immutable data structures, and use those as properties on this.state.

The upside of using immutable data structures is that the shallow update we get with this.setState() still works, and we can use React.addons.PureRenderMixin to get a boost in performance without any expensive deep equality checks.

So what does this do then?

This library provides an alternative version of React.addons.LinkedStateMixin that will let you "link" the value of your <input> with an ImmutableJS data strucutre.

So you can take advantage of all the good Immutable, nested data structure stuff we just talked about while still having the sugary, easy-to-use syntax of LinkedStateMixin.

Ok, how do I use it?

First, install it with npm install --save reactlink-immutable.

Then, just use it like you normally would with LinkedStateMixin; except pass an array of keys instead of a string.

var LinkedImmutableStateMixin = require('reactlink-immutable');
var Map = require('immutable').Map;
var WithImmutableLink = React.createClass({
  mixins: [LinkedImmutableStateMixin],
  getInitialState: function() {
    return { dog: Map({name: 'Sparky', kind: 'Lab'}) };
  },
  render: function() {
    return (
      <form>
        <input type="text" valueLink={this.linkImmutableState(['dog', 'name'])} />
        <input type="text" valueLink={this.linkImmutableState(['dog', 'kind'])} />
      </form>
    );
  }
});

Other notes

For convenience, a single string parameter is still supported for the key (rather than an array), which will make it behave like the standard this.linkState method.

Non-primatives

By default any non-primative Immutable values (such as Immutable.List or Immutable.Map) you link to will be converted to their plain JS equivalent via the Immutable toJS() function before passing them as value. However, there is an option for linkImmutableState that will disable this behavior if specified.

Ex: this.linkImmutableState(['myImmutable', 'myList'], { immutableValue: true }) will keep the myList value as an Immutable.List in the view instead of converting it to an Array.

Also, by default any non-primative, non-Immutable values (such as Array or Object) you link from your view state to will be converted to their Immutable equivalent via the Immutable fromJS() function before passing them back to your state. However, there is an option for linkImmutableState that will disable this behavior if specified.

Ex: this.linkImmutableState(['myImmutable', 'myArray'], { mutableState: true }) will keep the myArray value as an Array in the state instead of converting it to an Immutable.List.

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