added unit testing, and started implementing unit tests...phew
This commit is contained in:
Josh Burman
212
node_modules/array-from/polyfill.js
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vendored
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212
node_modules/array-from/polyfill.js
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// Production steps of ECMA-262, Edition 6, 22.1.2.1
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// Reference: http://www.ecma-international.org/ecma-262/6.0/#sec-array.from
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module.exports = (function() {
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var isCallable = function(fn) {
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return typeof fn === 'function';
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};
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var toInteger = function (value) {
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var number = Number(value);
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if (isNaN(number)) { return 0; }
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if (number === 0 || !isFinite(number)) { return number; }
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return (number > 0 ? 1 : -1) * Math.floor(Math.abs(number));
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};
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var maxSafeInteger = Math.pow(2, 53) - 1;
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var toLength = function (value) {
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var len = toInteger(value);
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return Math.min(Math.max(len, 0), maxSafeInteger);
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};
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var iteratorProp = function(value) {
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if(value != null) {
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if(['string','number','boolean','symbol'].indexOf(typeof value) > -1){
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return Symbol.iterator;
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} else if (
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(typeof Symbol !== 'undefined') &&
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('iterator' in Symbol) &&
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(Symbol.iterator in value)
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) {
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return Symbol.iterator;
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}
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// Support "@@iterator" placeholder, Gecko 27 to Gecko 35
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else if ('@@iterator' in value) {
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return '@@iterator';
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}
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}
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};
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var getMethod = function(O, P) {
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// Assert: IsPropertyKey(P) is true.
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if (O != null && P != null) {
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// Let func be GetV(O, P).
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var func = O[P];
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// ReturnIfAbrupt(func).
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// If func is either undefined or null, return undefined.
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if(func == null) {
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return void 0;
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}
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// If IsCallable(func) is false, throw a TypeError exception.
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if (!isCallable(func)) {
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throw new TypeError(func + ' is not a function');
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}
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return func;
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}
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};
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var iteratorStep = function(iterator) {
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// Let result be IteratorNext(iterator).
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// ReturnIfAbrupt(result).
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var result = iterator.next();
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// Let done be IteratorComplete(result).
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// ReturnIfAbrupt(done).
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var done = Boolean(result.done);
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// If done is true, return false.
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if(done) {
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return false;
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}
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// Return result.
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return result;
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};
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// The length property of the from method is 1.
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return function from(items /*, mapFn, thisArg */ ) {
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'use strict';
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// 1. Let C be the this value.
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var C = this;
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// 2. If mapfn is undefined, let mapping be false.
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var mapFn = arguments.length > 1 ? arguments[1] : void 0;
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var T;
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if (typeof mapFn !== 'undefined') {
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// 3. else
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// a. If IsCallable(mapfn) is false, throw a TypeError exception.
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if (!isCallable(mapFn)) {
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throw new TypeError(
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'Array.from: when provided, the second argument must be a function'
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);
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}
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// b. If thisArg was supplied, let T be thisArg; else let T
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// be undefined.
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if (arguments.length > 2) {
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T = arguments[2];
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}
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// c. Let mapping be true (implied by mapFn)
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}
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var A, k;
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// 4. Let usingIterator be GetMethod(items, @@iterator).
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// 5. ReturnIfAbrupt(usingIterator).
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var usingIterator = getMethod(items, iteratorProp(items));
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// 6. If usingIterator is not undefined, then
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if (usingIterator !== void 0) {
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// a. If IsConstructor(C) is true, then
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// i. Let A be the result of calling the [[Construct]]
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// internal method of C with an empty argument list.
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// b. Else,
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// i. Let A be the result of the abstract operation ArrayCreate
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// with argument 0.
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// c. ReturnIfAbrupt(A).
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A = isCallable(C) ? Object(new C()) : [];
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// d. Let iterator be GetIterator(items, usingIterator).
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var iterator = usingIterator.call(items);
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// e. ReturnIfAbrupt(iterator).
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if (iterator == null) {
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throw new TypeError(
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'Array.from requires an array-like or iterable object'
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);
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}
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// f. Let k be 0.
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k = 0;
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// g. Repeat
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var next, nextValue;
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while (true) {
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// i. Let Pk be ToString(k).
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// ii. Let next be IteratorStep(iterator).
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// iii. ReturnIfAbrupt(next).
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next = iteratorStep(iterator);
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// iv. If next is false, then
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if (!next) {
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// 1. Let setStatus be Set(A, "length", k, true).
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// 2. ReturnIfAbrupt(setStatus).
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A.length = k;
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// 3. Return A.
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return A;
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}
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// v. Let nextValue be IteratorValue(next).
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// vi. ReturnIfAbrupt(nextValue)
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nextValue = next.value;
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// vii. If mapping is true, then
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// 1. Let mappedValue be Call(mapfn, T, «nextValue, k»).
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// 2. If mappedValue is an abrupt completion, return
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// IteratorClose(iterator, mappedValue).
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// 3. Let mappedValue be mappedValue.[[value]].
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// viii. Else, let mappedValue be nextValue.
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// ix. Let defineStatus be the result of
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// CreateDataPropertyOrThrow(A, Pk, mappedValue).
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// x. [TODO] If defineStatus is an abrupt completion, return
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// IteratorClose(iterator, defineStatus).
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if (mapFn) {
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A[k] = mapFn.call(T, nextValue, k);
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}
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else {
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A[k] = nextValue;
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}
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// xi. Increase k by 1.
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k++;
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}
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// 7. Assert: items is not an Iterable so assume it is
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// an array-like object.
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} else {
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// 8. Let arrayLike be ToObject(items).
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var arrayLike = Object(items);
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// 9. ReturnIfAbrupt(items).
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if (items == null) {
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throw new TypeError(
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'Array.from requires an array-like object - not null or undefined'
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);
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}
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// 10. Let len be ToLength(Get(arrayLike, "length")).
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// 11. ReturnIfAbrupt(len).
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var len = toLength(arrayLike.length);
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// 12. If IsConstructor(C) is true, then
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// a. Let A be Construct(C, «len»).
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// 13. Else
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// a. Let A be ArrayCreate(len).
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// 14. ReturnIfAbrupt(A).
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A = isCallable(C) ? Object(new C(len)) : new Array(len);
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// 15. Let k be 0.
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k = 0;
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// 16. Repeat, while k < len… (also steps a - h)
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var kValue;
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while (k < len) {
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kValue = arrayLike[k];
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if (mapFn) {
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A[k] = mapFn.call(T, kValue, k);
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}
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else {
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A[k] = kValue;
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}
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k++;
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}
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// 17. Let setStatus be Set(A, "length", len, true).
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// 18. ReturnIfAbrupt(setStatus).
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A.length = len;
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// 19. Return A.
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}
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return A;
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};
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})();
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