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"use strict";
exports.__esModule = true;
exports.default = arrayFrom;
/**
* @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.
*/
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.js.map