core-js/modules/es.array.to-spliced.js

Standard library

'use strict';
var $ = require('../internals/export');
var addToUnscopables = require('../internals/add-to-unscopables');
var doesNotExceedSafeInteger = require('../internals/does-not-exceed-safe-integer');
var lengthOfArrayLike = require('../internals/length-of-array-like');
var toAbsoluteIndex = require('../internals/to-absolute-index');
var toIndexedObject = require('../internals/to-indexed-object');
var toIntegerOrInfinity = require('../internals/to-integer-or-infinity');
var createProperty = require('../internals/create-property');

var $Array = Array;
var max = Math.max;
var min = Math.min;

// `Array.prototype.toSpliced` method
// https://tc39.es/ecma262/#sec-array.prototype.tospliced
$({ target: 'Array', proto: true }, {
  toSpliced: function toSpliced(start, deleteCount /* , ...items */) {
    var O = toIndexedObject(this);
    var len = lengthOfArrayLike(O);
    var actualStart = toAbsoluteIndex(start, len);
    var argumentsLength = arguments.length;
    var k = 0;
    var insertCount, actualDeleteCount, newLen, A;
    if (argumentsLength === 0) {
      insertCount = actualDeleteCount = 0;
    } else if (argumentsLength === 1) {
      insertCount = 0;
      actualDeleteCount = len - actualStart;
    } else {
      insertCount = argumentsLength - 2;
      actualDeleteCount = min(max(toIntegerOrInfinity(deleteCount), 0), len - actualStart);
    }
    newLen = doesNotExceedSafeInteger(len + insertCount - actualDeleteCount);
    A = $Array(newLen);

    for (; k < actualStart; k++) createProperty(A, k, O[k]);
    for (; k < actualStart + insertCount; k++) createProperty(A, k, arguments[k - actualStart + 2]);
    for (; k < newLen; k++) createProperty(A, k, O[k + actualDeleteCount - insertCount]);

    return A;
  }
});

addToUnscopables('toSpliced');