shim.js
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"use strict";
var iteratorSymbol = require("es6-symbol").iterator
, isArguments = require("../../function/is-arguments")
, isFunction = require("../../function/is-function")
, toPosInt = require("../../number/to-pos-integer")
, callable = require("../../object/valid-callable")
, validValue = require("../../object/valid-value")
, isValue = require("../../object/is-value")
, isString = require("../../string/is-string")
, isArray = Array.isArray
, call = Function.prototype.call
, desc = { configurable: true, enumerable: true, writable: true, value: null }
, defineProperty = Object.defineProperty;
// eslint-disable-next-line complexity, max-lines-per-function
module.exports = function (arrayLike /*, mapFn, thisArg*/) {
var mapFn = arguments[1]
, thisArg = arguments[2]
, Context
, i
, j
, arr
, length
, code
, iterator
, result
, getIterator
, value;
arrayLike = Object(validValue(arrayLike));
if (isValue(mapFn)) callable(mapFn);
if (!this || this === Array || !isFunction(this)) {
// Result: Plain array
if (!mapFn) {
if (isArguments(arrayLike)) {
// Source: Arguments
length = arrayLike.length;
if (length !== 1) return Array.apply(null, arrayLike);
arr = new Array(1);
arr[0] = arrayLike[0];
return arr;
}
if (isArray(arrayLike)) {
// Source: Array
arr = new Array(length = arrayLike.length);
for (i = 0; i < length; ++i) arr[i] = arrayLike[i];
return arr;
}
}
arr = [];
} else {
// Result: Non plain array
Context = this;
}
if (!isArray(arrayLike)) {
if ((getIterator = arrayLike[iteratorSymbol]) !== undefined) {
// Source: Iterator
iterator = callable(getIterator).call(arrayLike);
if (Context) arr = new Context();
result = iterator.next();
i = 0;
while (!result.done) {
value = mapFn ? call.call(mapFn, thisArg, result.value, i) : result.value;
if (Context) {
desc.value = value;
defineProperty(arr, i, desc);
} else {
arr[i] = value;
}
result = iterator.next();
++i;
}
length = i;
} else if (isString(arrayLike)) {
// Source: String
length = arrayLike.length;
if (Context) arr = new Context();
for (i = 0, j = 0; i < length; ++i) {
value = arrayLike[i];
if (i + 1 < length) {
code = value.charCodeAt(0);
// eslint-disable-next-line max-depth
if (code >= 0xd800 && code <= 0xdbff) value += arrayLike[++i];
}
value = mapFn ? call.call(mapFn, thisArg, value, j) : value;
if (Context) {
desc.value = value;
defineProperty(arr, j, desc);
} else {
arr[j] = value;
}
++j;
}
length = j;
}
}
if (length === undefined) {
// Source: array or array-like
length = toPosInt(arrayLike.length);
if (Context) arr = new Context(length);
for (i = 0; i < length; ++i) {
value = mapFn ? call.call(mapFn, thisArg, arrayLike[i], i) : arrayLike[i];
if (Context) {
desc.value = value;
defineProperty(arr, i, desc);
} else {
arr[i] = value;
}
}
}
if (Context) {
desc.value = null;
arr.length = length;
}
return arr;
};