# Utils

Set of useful methods.

Module is a part of core functionality so you don't need to install it.

## Link

	var utils = require('utils');

## API

### Object

	mixin(target, source, keys)

Copies properties from `source` object to `target` object. Returns target object. `keys` - array of property names to copy (if not specified - all properties will be copied).

	toObject(keys, values)

Creates an object using `keys` as property names and `values` as property values.

	mapToArray(map)

Represents `map` as array of its elements. Each element in the array is maps element extended with its id in the map. Example:

	var object = {
			value1: { number: 3 },
			value2: { number: 4 }
		};

	utils.mapToArray(object); // [{ id: 'value1', number: 3 }, { id: 'value2', number: 4 }]

### The primitives

	template(string, data)

 * `string` - template
 * `data` - data object

[Interpolation](http://en.wikipedia.org/wiki/String_interpolation) of string. Example:

	utils.template('Hello {name}', { name: 'Ann' }); // 'Hello Ann'

Insert the data from the `data` in pattern string.

	rangeValue(value, min, max)

If `value` is beyond the range `[min..max]` the nearest limit will be returned. Example:

	utils.rangeValue(10, 2, 5); // 5
	utils.rangeValue(0, 2, 5); // 2
	utils.rangeValue(3, 2, 5); // 3

### Others

	dispatchEvent(target, event, options)

 * `target` - element which receives event
 * `event` - event name
 * `options` - object with settings, transferred to constructor `CustomEvent`.

Options can include a field `detail` for transmission of additional information.

	load(url, callback, async)

Simple [XMLHttpRequest](https://developer.mozilla.org/en-US/docs/Web/API/XMLHttpRequest).

### Observer

To create instance of Observer user `Observer` constructor:

	var observer = new utils.Observer();

Instance of constructor has the following methods:

* `subscribe(event, callback)` - adds callback for event. When event publishes `Observer` executes `callback`

* `unsubscribe(event, callback)` - removes `callback` listener for event `event`

* `publish(event, data)` - create an event `event` and send `data` to all listeners of this event.

* `destroy()` - removes all added subscriptions