You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
94 lines
2.6 KiB
94 lines
2.6 KiB
2 years ago
|
/**
|
||
|
|
* @source {https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/from#Polyfill}
|
||
|
|
* but without thisArg (too hard to type, no need to `this`)
|
||
|
|
*/
|
||
|
|
var toStr = Object.prototype.toString;
|
||
|
|
|
||
|
|
function isCallable(fn) {
|
||
|
|
return typeof fn === "function" || toStr.call(fn) === "[object Function]";
|
||
|
|
}
|
||
|
|
|
||
|
|
function toInteger(value) {
|
||
|
|
var number = Number(value);
|
||
|
|
|
||
|
|
if (isNaN(number)) {
|
||
|
|
return 0;
|
||
|
|
}
|
||
|
|
|
||
|
|
if (number === 0 || !isFinite(number)) {
|
||
|
|
return number;
|
||
|
|
}
|
||
|
|
|
||
|
|
return (number > 0 ? 1 : -1) * Math.floor(Math.abs(number));
|
||
|
|
}
|
||
|
|
|
||
|
|
var maxSafeInteger = Math.pow(2, 53) - 1;
|
||
|
|
|
||
|
|
function toLength(value) {
|
||
|
|
var len = toInteger(value);
|
||
|
|
return Math.min(Math.max(len, 0), maxSafeInteger);
|
||
|
|
}
|
||
|
|
/**
|
||
|
|
* Creates an array from an iterable object.
|
||
|
|
* @param iterable An iterable object to convert to an array.
|
||
|
|
*/
|
||
|
|
|
||
|
|
|
||
|
|
/**
|
||
|
|
* Creates an array from an iterable object.
|
||
|
|
* @param iterable An iterable object to convert to an array.
|
||
|
|
* @param mapfn A mapping function to call on every element of the array.
|
||
|
|
* @param thisArg Value of 'this' used to invoke the mapfn.
|
||
|
|
*/
|
||
|
|
export default function arrayFrom(arrayLike, mapFn) {
|
||
|
|
// 1. Let C be the this value.
|
||
|
|
// edit(@eps1lon): we're not calling it as Array.from
|
||
|
|
var C = Array; // 2. Let items be ToObject(arrayLike).
|
||
|
|
|
||
|
|
var items = Object(arrayLike); // 3. ReturnIfAbrupt(items).
|
||
|
|
|
||
|
|
if (arrayLike == null) {
|
||
|
|
throw new TypeError("Array.from requires an array-like object - not null or undefined");
|
||
|
|
} // 4. If mapfn is undefined, then let mapping be false.
|
||
|
|
// const mapFn = arguments.length > 1 ? arguments[1] : void undefined;
|
||
|
|
|
||
|
|
|
||
|
|
if (typeof mapFn !== "undefined") {
|
||
|
|
// 5. else
|
||
|
|
// 5. a If IsCallable(mapfn) is false, throw a TypeError exception.
|
||
|
|
if (!isCallable(mapFn)) {
|
||
|
|
throw new TypeError("Array.from: when provided, the second argument must be a function");
|
||
|
|
}
|
||
|
|
} // 10. Let lenValue be Get(items, "length").
|
||
|
|
// 11. Let len be ToLength(lenValue).
|
||
|
|
|
||
|
|
|
||
|
|
var len = toLength(items.length); // 13. If IsConstructor(C) is true, then
|
||
|
|
// 13. a. Let A be the result of calling the [[Construct]] internal method
|
||
|
|
// of C with an argument list containing the single item len.
|
||
|
|
// 14. a. Else, Let A be ArrayCreate(len).
|
||
|
|
|
||
|
|
var A = isCallable(C) ? Object(new C(len)) : new Array(len); // 16. Let k be 0.
|
||
|
|
|
||
|
|
var k = 0; // 17. Repeat, while k < len… (also steps a - h)
|
||
|
|
|
||
|
|
var kValue;
|
||
|
|
|
||
|
|
while (k < len) {
|
||
|
|
kValue = items[k];
|
||
|
|
|
||
|
|
if (mapFn) {
|
||
|
|
A[k] = mapFn(kValue, k);
|
||
|
|
} else {
|
||
|
|
A[k] = kValue;
|
||
|
|
}
|
||
|
|
|
||
|
|
k += 1;
|
||
|
|
} // 18. Let putStatus be Put(A, "length", len, true).
|
||
|
|
|
||
|
|
|
||
|
|
A.length = len; // 20. Return A.
|
||
|
|
|
||
|
|
return A;
|
||
|
|
}
|
||
|
|
//# sourceMappingURL=array.from.mjs.map
|