ampersand-dom-bindings

Takes binding declarations and returns key-tree-store of functions that can be used to apply those bindings.

ampersand-dom-bindings

Part of the [Ampersand.js toolkit](http://ampersandjs.com) for building clientside applications.

Takes binding declarations as described below and returns key-tree-store of functions that can be used to apply those bindings to a DOM tree.

ampersand-view use this for declarative bindings.

The returned functions should be called with these arguments: The root element, the current value of the property, and a name for the binding types where that is relevant.

npm install ampersand-dom-bindings

sets/maintains textContent of selected element. treats , null, and NaN as ''

'model.key': {
    type: 'text',
    selector: '.someSelector' // or hook 
}

sets and maintains single class as string that matches value of property

  • handles removing previous class if there was one
  • treats , null, and NaN as '' (empty string).
'model.key': {
    type: 'class',
    selector: // or hook 
}

sets the whole attribute to match value of property. treats , null, and NaN as '' (empty string). name can also be an array to set multiple attributes to the same value.

'model.key': {
    type: 'attribute',
    selector: '#something', // or hook 
    name: 'width'
}

sets the value of the element to match value of the property. works well for input, select, and textarea elements. treats , null, and NaN as '' (empty string).

note: The binding will only be applied if the element is not currently in focus. This is done by checking to see if the element is the document.activeElement first. The reason it works this way is because if you've set up two-way data bindings you get a circular event: the input changes, which sets the bound model property, which in turn updates the value of the input. This might sound OK but results in the cursor always jumping to the end of the input/textarea. So if you're editing the middle of a bound text field, the cursor keeps jumping to the end. We avoid this by making sure it's not already in focus thus avoiding the bad loop.

'model.key': {
    type: 'value',
    selector: '#something', // or hook 
}

add/removes class based on boolean interpretation of property name. name, yes, or no can also be an array of class names where all the values will be toggled.

'model.active': {
    type: 'booleanClass',
    selector: '#something', // or hook 
    // to specify name of class to toggle (if different than key name) 
    // you could either specify a name 
    name: 'active'
    // or a yes/no case 
    yes: 'active',
    no: 'not-active'
}

toggles whole attribute on the element (think checked) based on boolean interpretation of property name. name can also be an array of attribute names where all the values will be toggled.

'model.isAwesome': {
    type: 'booleanAttribute',
    selector: '#something', // or hook 
    name: 'checked'
}

toggles visibility (using display: none) of entire element based on boolean interpretation of property.

// simple show/hide of single element 
'model.key': {
    type: 'toggle',
    selector: '#something' // or hook 
}
 
// show/hide where true/false show different things 
'model.key': {
    type: 'toggle',
    yes: '#true_case',
    no: '#false_case'
}

Toggles existence of multiple items based on value of property.

'model.activetab': {
    type: 'switch',
    cases: {
        'edit': '#edit_tab',
        'new': '#new_tab',
        'details': '#details_tab'
    }
}

Toggles existence of a class on multiple elements based on value of property.

'model.key': {
    type: 'switchClass',
    name: 'is-active',
    cases: {
        'edit': '#edit_tab',
        'new': '#new_tab',
        'details': '#details_tab'
    }
}

renders innerHTML, can be a string or DOM, based on property value of model

'model.key': {
    type: 'innerHTML',
    selector: '#something' // or hook 
}

type can also be a function. It will be run for each matching el with the value and previousValue of the property. The function is bound to the view declaring the bindings, so this refers to the view.

'model.key': {
    typefunction (elvaluepreviousValue) {
        // Do something custom to el 
        // using value and/or previousValue 
    },
    selector: '#something', // or hook 
}

If given an array, then treat each contained item as separate binding

'model.key': [
    {
        type: 'booleanClass',
        selector: '#something', // or hook 
        name: 'active' // (optional) name of class to toggle if different than key name 
    },
    {
        type: 'attribute',
        selector: '#something', // or hook 
        name: 'width'
    }
]

The attribute, booleanAttribute and booleanClass types also accept an array for the name property (and yes/no for booleanClass). All the values in the array will be set the same as if each were bound separately.

'model.key': {
    // Also works with booleanAttribute and booleanClass 
    type: 'attribute',
    selector: '#avatar',
    // Both height and width will be bound to model.key 
    name: ['height', 'width']
}

We've started using this convention a lot, rather than using classes and IDs in JS to select elements within a view, we use the data-hook attribute. This lets designers edit templates without fear of breaking something by changing a class. It works wonderfully, but the only thing that sucks about that is the syntax of attribute selectors: [data-hook=some-hook] is a bit annoying to type a million types, and also in JS-land when coding and we see [ we always assume arrays.

So for each of these bindings you can either use selector or hook, so these two would be equivalent:

'model.key': {
    selector: '[data-hook=my-element]'
}
 
'model.key': {
    hook: 'my-element'
}
 
'model.key': '#something' // creates `text` binding for that selector and property 
 
// `type` defaults to `text` so we can also do 
'model.key': {
    hook: 'hook-name'
}
var View = require('ampersand-view');
var templates = require('../templates');
 
 
module.exports = View.extend({
    template: templates.includes.app,
    bindings: {
        'model.client_name': {
            hook: 'name'
        },
        'model.logo_uri': {
            type: 'attribute',
            name: 'src',
            hook: 'icon'
        }
    }
});

Previously after having given views the ability to have their own properties (since view inherits from state) it was awkward to bind those to the DOM. Also, for binding things that were not just this.model the syntax had to change.

Now this is fairly simple/obvious:

module.exports = View.extend({
    template: templates.includes.app,
    props: {
        activetab: 'string',
        person: 'state',
        meeting: 'state'
    },
    bindings: {
        // for the property that's directly on the view 
        'activetab': {
            type: 'switch',
            case: {
                'edit': '#edit_tab',
                'new': '#new_tab',
                'details': '#details_tab'
            }
        },
        // this one is for one model 
        'person.full_name': '[data-hook=name]',
        // this one is for another model 
        'meeting.subject': '[data-hook=subject]'
    }
});
  • 3.3.1 - Fix issues with yes/no handling in boolean class. Add lots of tests.

MIT