32 lines
1.1 KiB
JavaScript
32 lines
1.1 KiB
JavaScript
'use strict';
|
|
var toObject = require('../internals/to-object');
|
|
var toAbsoluteIndex = require('../internals/to-absolute-index');
|
|
var lengthOfArrayLike = require('../internals/length-of-array-like');
|
|
var deletePropertyOrThrow = require('../internals/delete-property-or-throw');
|
|
|
|
var min = Math.min;
|
|
|
|
// `Array.prototype.copyWithin` method implementation
|
|
// https://tc39.es/ecma262/#sec-array.prototype.copywithin
|
|
// eslint-disable-next-line es/no-array-prototype-copywithin -- safe
|
|
module.exports = [].copyWithin || function copyWithin(target /* = 0 */, start /* = 0, end = @length */) {
|
|
var O = toObject(this);
|
|
var len = lengthOfArrayLike(O);
|
|
var to = toAbsoluteIndex(target, len);
|
|
var from = toAbsoluteIndex(start, len);
|
|
var end = arguments.length > 2 ? arguments[2] : undefined;
|
|
var count = min((end === undefined ? len : toAbsoluteIndex(end, len)) - from, len - to);
|
|
var inc = 1;
|
|
if (from < to && to < from + count) {
|
|
inc = -1;
|
|
from += count - 1;
|
|
to += count - 1;
|
|
}
|
|
while (count-- > 0) {
|
|
if (from in O) O[to] = O[from];
|
|
else deletePropertyOrThrow(O, to);
|
|
to += inc;
|
|
from += inc;
|
|
} return O;
|
|
};
|