fabric.js/src/util/lang_array.js

(function() {

  var slice = Array.prototype.slice;

  if (!Array.prototype.indexOf) {
    /**
     * Finds index of an element in an array
     * @param {Any} searchElement
     * @param {Number} [fromIndex]
     * @return {Number}
     */
    Array.prototype.indexOf = function (searchElement /*, fromIndex */ ) {
      if (this === void 0 || this === null) {
        throw new TypeError();
      }
      var t = Object(this), len = t.length >>> 0;
      if (len === 0) {
        return -1;
      }
      var n = 0;
      if (arguments.length > 0) {
        n = Number(arguments[1]);
        if (n !== n) { // shortcut for verifying if it's NaN
          n = 0;
        }
        else if (n !== 0 && n !== Number.POSITIVE_INFINITY && n !== Number.NEGATIVE_INFINITY) {
          n = (n > 0 || -1) * Math.floor(Math.abs(n));
        }
      }
      if (n >= len) {
        return -1;
      }
      var k = n >= 0 ? n : Math.max(len - Math.abs(n), 0);
      for (; k < len; k++) {
        if (k in t && t[k] === searchElement) {
          return k;
        }
      }
      return -1;
    };
  }

  if (!Array.prototype.forEach) {
    /**
     * Iterates an array, invoking callback for each element
     * @param {Function} fn Callback to invoke for each element
     * @param {Object} [context] Context to invoke callback in
     * @return {Array}
     */
    Array.prototype.forEach = function(fn, context) {
      for (var i = 0, len = this.length >>> 0; i < len; i++) {
        if (i in this) {
          fn.call(context, this[i], i, this);
        }
      }
    };
  }

  if (!Array.prototype.map) {
    /**
     * Returns a result of iterating over an array, invoking callback for each element
     * @param {Function} fn Callback to invoke for each element
     * @param {Object} [context] Context to invoke callback in
     * @return {Array}
     */
    Array.prototype.map = function(fn, context) {
      var result = [ ];
      for (var i = 0, len = this.length >>> 0; i < len; i++) {
        if (i in this) {
          result[i] = fn.call(context, this[i], i, this);
        }
      }
      return result;
    };
  }

  if (!Array.prototype.every) {
    /**
     * Returns true if a callback returns truthy value for all elements in an array
     * @param {Function} fn Callback to invoke for each element
     * @param {Object} [context] Context to invoke callback in
     * @return {Boolean}
     */
    Array.prototype.every = function(fn, context) {
      for (var i = 0, len = this.length >>> 0; i < len; i++) {
        if (i in this && !fn.call(context, this[i], i, this)) {
          return false;
        }
      }
      return true;
    };
  }

  if (!Array.prototype.some) {
    /**
     * Returns true if a callback returns truthy value for at least one element in an array
     * @param {Function} fn Callback to invoke for each element
     * @param {Object} [context] Context to invoke callback in
     * @return {Boolean}
     */
    Array.prototype.some = function(fn, context) {
      for (var i = 0, len = this.length >>> 0; i < len; i++) {
        if (i in this && fn.call(context, this[i], i, this)) {
          return true;
        }
      }
      return false;
    };
  }

  if (!Array.prototype.filter) {
    /**
     * Returns the result of iterating over elements in an array
     * @param {Function} fn Callback to invoke for each element
     * @param {Object} [context] Context to invoke callback in
     * @return {Array}
     */
    Array.prototype.filter = function(fn, context) {
      var result = [ ], val;
      for (var i = 0, len = this.length >>> 0; i < len; i++) {
        if (i in this) {
          val = this[i]; // in case fn mutates this
          if (fn.call(context, val, i, this)) {
            result.push(val);
          }
        }
      }
      return result;
    };
  }

  if (!Array.prototype.reduce) {
    /**
     * Returns "folded" (reduced) result of iterating over elements in an array
     * @param {Function} fn Callback to invoke for each element
     * @param {Object} [context] Context to invoke callback in
     * @return {Any}
     */
    Array.prototype.reduce = function(fn /*, initial*/) {
      var len = this.length >>> 0,
          i = 0,
          rv;

      if (arguments.length > 1) {
        rv = arguments[1];
      }
      else {
        do {
          if (i in this) {
            rv = this[i++];
            break;
          }
          // if array contains no values, no initial value to return
          if (++i >= len) {
            throw new TypeError();
          }
        }
        while (true);
      }
      for (; i < len; i++) {
        if (i in this) {
          rv = fn.call(null, rv, this[i], i, this);
        }
      }
      return rv;
    };
  }

  /**
   * Invokes method on all items in a given array
   * @memberOf fabric.util.array
   * @param {Array} array Array to iterate over
   * @param {String} method Name of a method to invoke
   * @return {Array}
   */
  function invoke(array, method) {
    var args = slice.call(arguments, 2), result = [ ];
    for (var i = 0, len = array.length; i < len; i++) {
      result[i] = args.length ? array[i][method].apply(array[i], args) : array[i][method].call(array[i]);
    }
    return result;
  }

  /**
   * Finds maximum value in array (not necessarily "first" one)
   * @memberOf fabric.util.array
   * @param {Array} array Array to iterate over
   * @param {String} byProperty
   * @return {Any}
   */
  function max(array, byProperty) {
    if (!array || array.length === 0) return undefined;

    var i = array.length - 1,
        result = byProperty ? array[i][byProperty] : array[i];
    if (byProperty) {
      while (i--) {
        if (array[i][byProperty] >= result) {
          result = array[i][byProperty];
        }
      }
    }
    else {
      while (i--) {
        if (array[i] >= result) {
          result = array[i];
        }
      }
    }
    return result;
  }

  /**
   * Finds minimum value in array (not necessarily "first" one)
   * @memberOf fabric.util.array
   * @param {Array} array Array to iterate over
   * @param {String} byProperty
   * @return {Any}
   */
  function min(array, byProperty) {
    if (!array || array.length === 0) return undefined;

    var i = array.length - 1,
        result = byProperty ? array[i][byProperty] : array[i];

    if (byProperty) {
      while (i--) {
        if (array[i][byProperty] < result) {
          result = array[i][byProperty];
        }
      }
    }
    else {
      while (i--) {
        if (array[i] < result) {
          result = array[i];
        }
      }
    }
    return result;
  }

  /**
   * @namespace fabric.util.array
   */
  fabric.util.array = {
    invoke: invoke,
    min: min,
    max: max
  };

})();