diff options
| -rw-r--r-- | src/apis.js | 56 | ||||
| -rw-r--r-- | test/ApiSpecs.js | 30 | 
2 files changed, 86 insertions, 0 deletions
| diff --git a/src/apis.js b/src/apis.js index a9a9379d..b34f131a 100644 --- a/src/apis.js +++ b/src/apis.js @@ -19,6 +19,25 @@ var angularCollection = {  var angularObject = {    'extend': extend  }; + +/** + * @workInProgress + * @ngdoc overview + * @name angular.Array + * + * @description + * Utility functions for manipulation with JavaScript Array objects. + * + * These functions are exposed in two ways: + * + * - **in angular expressions**: the functions are bound to the Array objects and augment the Array + *   type as array methods. The names of these methods are prefixed with `$` character to minimize + *   naming collisions. To call a method, invoke `myArrayObject.$foo(params)`. + * + * - **in JavaScript code**: the functions don't augment the Array type and must be invoked as + *   functions of `angular.Array` as `angular.Array.foo(myArrayObject, params)`. + * + */  var angularArray = {    'indexOf': indexOf,    'sum':function(array, expression) { @@ -173,7 +192,44 @@ var angularArray = {          return t1 < t2 ? -1 : 1;        }      } +  }, + + +  /** +   * @workInProgress +   * @ngdoc function +   * @name angular.Array.limitTo +   * @function +   * +   * @description +   * Creates a new array containing only the first, or last `limit` number of elements of the +   * source `array`. +   * +   * @param {Array} array Source array to be limited. +   * @param {string|Number} limit The length of the returned array. If the number is positive, the +   *     first `limit` items from the source array will be copied, if the number is negative, the +   *     last `limit` items will be copied. +   * @returns {Array} New array of length `limit`. +   * +   */ +  limitTo: function(array, limit) { +    limit = parseInt(limit, 10); +    var out = [], +        i, n; + +    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;    }  }; diff --git a/test/ApiSpecs.js b/test/ApiSpecs.js index 81fd9155..e2a68a61 100644 --- a/test/ApiSpecs.js +++ b/test/ApiSpecs.js @@ -115,6 +115,36 @@ describe('api', function(){    }); +  describe('limit', function() { +    var items; + +    beforeEach(function() { +      items = ['a', 'b', 'c', 'd', 'e', 'f', 'g', 'h']; +    }); + + +    it('should return the first X items when X is positive', function() { +      expect(angular.Array.limitTo(items, 3)).toEqual(['a', 'b', 'c']); +      expect(angular.Array.limitTo(items, '3')).toEqual(['a', 'b', 'c']); +    }); + + +    it('should return the last X items when X is negative', function() { +      expect(angular.Array.limitTo(items, -3)).toEqual(['f', 'g', 'h']); +      expect(angular.Array.limitTo(items, '-3')).toEqual(['f', 'g', 'h']); +    }); + + +    it('should return an empty array when X cannot be parsed', function() { +      expect(angular.Array.limitTo(items, 'bogus')).toEqual([]); +      expect(angular.Array.limitTo(items, 'null')).toEqual([]); +      expect(angular.Array.limitTo(items, 'undefined')).toEqual([]); +      expect(angular.Array.limitTo(items, null)).toEqual([]); +      expect(angular.Array.limitTo(items, undefined)).toEqual([]); +    }) +  }); + +    it('Add', function(){      var add = angular.Array.add;      assertJsonEquals([{}, "a"], add(add([]),"a")); | 
