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/** * @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
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