src/array/shim.js
/* istanbul ignore if */
if (typeof define !== "function") {
var define = require("amdefine")(module);
}
define(function (require) {
"use strict";
/*meta({
"name": "Array",
"type": "class",
"global": true
})
meta({
"name": "forEach",
"shim": true,
"description": "Executes a provided function once per array element.",
"arguments": [{
"name": "callback",
"type": "function",
"description": "Function to execute for each element."
}, {
"name": "context",
"type": "object",
"description": "Object to use as this when executing callback.",
"required": false
}]
})
meta({
"name": "indexOf",
"shim": true,
"description": "Returns the first index at which a given element can be found in the array, or -1 if it is not present.",
"arguments": [{
"name": "element",
"type": "any"
}, {
"name": "from",
"type": "number",
"required": false,
"description": "The index to start the search"
}],
"returns": "number"
})
meta({
"name": "lastIndexOf",
"shim": true,
"description": "Returns the last index at which a given element can be found in the array, or -1 if it is not present.",
"arguments": [{
"name": "element",
"type": "any"
}, {
"name": "from",
"type": "number",
"required": false,
"description": "The index to start the search"
}],
"returns": "number"
})
meta({
"name": "map",
"shim": true,
"description": "Creates a new array with the results of calling a provided function on every element in this array.",
"arguments": [{
"name": "callback",
"type": "function",
"description": "Function that produces an element of the new Array from an element of the current one."
}, {
"name": "context",
"type": "object",
"description": "Object to use as this when executing callback."
}],
"returns": "array"
})
meta({
"name": "filter",
"shim": true,
"description": "Creates a new array with all elements that pass the test implemented by the provided function.",
"arguments": [{
"name": "callback",
"type": "function",
"description": "Function to test each element of the array."
}, {
"name": "context",
"type": "object",
"description": "Object to use as this when executing callback."
}],
"returns": "array"
})
meta({
"name": "find",
"shim": true,
"description": "Finds the first value that returns true from the callback.",
"arguments": [{
"name": "callback",
"type": "function",
"description": "Function to test each element of the array."
}, {
"name": "context",
"type": "object",
"description": "Object to use as this when executing callback."
}],
"returns": "any"
})
meta({
"name": "findIndex",
"shim": true,
"description": "Finds the index of the first value that returns true from the callback",
"arguments": [{
"name": "callback",
"type": "function",
"description": "Function to test each element of the array."
}, {
"name": "context",
"type": "object",
"description": "Object to use as this when executing callback."
}],
"returns": "number"
})
meta({
"name": "reduce",
"shim": true,
"description": "Apply a function against an accumulator and each value of the array (from left-to-right) as to reduce it to a single value.",
"arguments": [{
"name": "callback",
"type": "function",
"description": "Function to execute on each value in the array. Each return is passed to the next execution."
}, {
"name": "initialValue",
"type": "any",
"description": "Value to be use as the first argument to the first call of the callback."
}],
"returns": "array"
})
meta({
"name": "every",
"shim": true,
"description": "Tests whether all elements in the array pass the test implemented by callback",
"arguments": [{
"name": "callback",
"type": "function",
"description": "Function to execute for each element"
}, {
"name": "context",
"type": "object",
"description": "Object to use as this when executing callback",
"required": false
}],
"returns": {
"type": "boolean",
"description": "True if callback returns a truthy value for each item"
}
})
meta({
"name": "some",
"shim": true,
"description": "Tests whether some element in the array passes the test implemented by callback",
"arguments": [{
"name": "callback",
"type": "function",
"description": "Function to execute for each element"
}, {
"name": "context",
"type": "object",
"description": "Object to use as this when executing callback",
"required": false
}],
"returns": {
"type": "boolean",
"description": "True if callback returns a truthy value for any item"
}
})*/
require("../class/shim");
var methods = [
"forEach",
"reduce",
"indexOf",
"lastIndexOf",
"map",
"fill",
"find",
"findIndex",
"filter",
"every",
"some"
],
shims = {};
shims.forEach = function(callback, context) {
var i = 0,
len = this.length;
for (; i < len; i += 1) {
callback.call(context, this[i], i, this);
}
};
shims.reduce = function (callback, initialValue) {
var initialValueIsEmpty = "undefined" === typeof initialValue,
value = initialValue;
this.forEach(function (element, index, array) {
if (initialValueIsEmpty && 0 === index) {
value = element;
} else {
value = callback(value, element, index, array);
}
});
return value;
};
shims.indexOf = function (element, from) {
var length = this.length,
found = -1,
index = normalizeFrom(from || 0, length);
for (; index < length; index += 1) {
if (this[index] === element) {
found = index;
break;
}
}
return found;
};
shims.lastIndexOf = function (element, from) {
var length = this.length,
found = -1,
index = normalizeFrom(from || length, length);
for (; index >= 0; index -= 1) {
if (this[index] === element) {
found = index;
break;
}
}
return found;
};
function normalizeFrom (from, length) {
if (from < 0) {
from = atLeastZero(from + length);
}
return from;
}
function atLeastZero (number) {
return Math.max(number, 0);
}
shims.map = function (callback, context) {
/* jshint -W072 */ //native APIs have 4 parameters
return this.reduce(function (mapped, element, index, array) {
mapped[index] = callback.call(context, element, index, array);
return mapped;
}, []);
};
shims.filter = function (callback, context) {
/* jshint -W072 */ //native APIs have 4 parameters
return this.reduce(function (filtered, element, index, array) {
if (callback.call(context, element, index, array)) {
filtered.push(element);
}
return filtered;
}, []);
};
shims.find = function (callback, context) {
var index = this.findIndex(callback, context);
return this[index];
};
shims.findIndex = function (callback, context) {
var length = this.length,
index = 0,
element,
found = -1;
for (; index < length; index += 1) {
element = this[index];
/* jshint -W072 */ //native APIs have 4 parameters
if (callback.call(context, element, index, this)) {
found = index;
break;
}
}
return found;
};
shims.every = function (callback, context) {
/* jshint -W072 */ //native APIs have 4 parameters
return this.reduce(function (result, element, index, array) {
if (result) {
result = !!callback.call(context, element, index, array);
}
return result;
}, true);
};
shims.some = function (callback, context) {
/* jshint -W072 */ //native APIs have 4 parameters
return this.reduce(function (result, element, index, array) {
if (!result) {
result = !!callback.call(context, element, index, array);
}
return result;
}, false);
};
shims.fill = function (element, from, to) {
var length = this.length,
index = normalizeFrom(from || 0, length),
end = normalizeFrom(to || length, length);
for (; index < end; index += 1) {
this[index] = element;
}
return this;
};
Array.shim("forEach", shims.forEach);
methods.forEach(attachIfUndefined);
function attachIfUndefined (method) {
Array.shim(method, shims[method]);
}
return shims;
});