'use strict';

/**

* @ngdoc function

* @name ng.filter:limitTo

* @function

*

* @description

* Creates a new array containing only a specified number of elements in an array. The elements

* are taken from either the beginning or the end of the source array, as specified by the

* value and sign (positive or negative) of `limit`.

*

* Note: This function is used to augment the `Array` type in Angular expressions. See

* {@link ng.$filter} for more information about Angular arrays.

*

* @param {Array} array Source array to be limited.

* @param {string|Number} limit The length of the returned array. If the `limit` number is

* positive, `limit` number of items from the beginning of the source array are copied.

* If the number is negative, `limit` number of items from the end of the source array are

* copied. The `limit` will be trimmed if it exceeds `array.length`

* @returns {Array} A new sub-array of length `limit` or less if input array had less than `limit`

* elements.

*

* @example

<doc:example>

<doc:source>

<script>

function Ctrl($scope) {

$scope.numbers = [1,2,3,4,5,6,7,8,9];

$scope.limit = 3;

}

</script>

<div ng-controller="Ctrl">

Limit {{numbers}} to: <input type="integer" ng-model="limit">

<p>Output: {{ numbers | limitTo:limit }}</p>

</div>

</doc:source>

<doc:scenario>

it('should limit the numer array to first three items', function() {

expect(element('.doc-example-live input[ng-model=limit]').val()).toBe('3');

expect(binding('numbers | limitTo:limit')).toEqual('[1,2,3]');

});

it('should update the output when -3 is entered', function() {

input('limit').enter(-3);

expect(binding('numbers | limitTo:limit')).toEqual('[7,8,9]');

});

it('should not exceed the maximum size of input array', function() {

input('limit').enter(100);

expect(binding('numbers | limitTo:limit')).toEqual('[1,2,3,4,5,6,7,8,9]');

});

</doc:scenario>

</doc:example>

*/

function limitToFilter(){

return function(array, limit) {

if (!(array instanceof Array)) return array;

limit = int(limit);

var out = [],

i, n;

// check that array is iterable

if (!array || !(array instanceof Array))

return out;

// if abs(limit) exceeds maximum length, trim it

if (limit > array.length)

limit = array.length;

else if (limit < -array.length)

limit = -array.length;

if (limit > 0) {

i = 0;

n = limit;

} else {

i = array.length + limit;

n = array.length;

}

for (; i<n; i++) {

out.push(array[i]);

}

return out;

}

}