esnext.typed-array.to-spliced.js

'use strict';
// TODO: Remove from `core-js@4`
var ArrayBufferViewCore = require('../internals/array-buffer-view-core');
var lengthOfArrayLike = require('../internals/length-of-array-like');
var isBigIntArray = require('../internals/is-big-int-array');
var toAbsoluteIndex = require('../internals/to-absolute-index');
var toBigInt = require('../internals/to-big-int');
var toIntegerOrInfinity = require('../internals/to-integer-or-infinity');
var fails = require('../internals/fails');

var aTypedArray = ArrayBufferViewCore.aTypedArray;
var getTypedArrayConstructor = ArrayBufferViewCore.getTypedArrayConstructor;
var exportTypedArrayMethod = ArrayBufferViewCore.exportTypedArrayMethod;
var max = Math.max;
var min = Math.min;

// some early implementations, like WebKit, does not follow the final semantic
var PROPER_ORDER = !fails(function () {
  // eslint-disable-next-line es/no-typed-arrays -- required for testing
  var array = new Int8Array([1]);

  var spliced = array.toSpliced(1, 0, {
    valueOf: function () {
      array[0] = 2;
      return 3;
    }
  });

  return spliced[0] !== 2 || spliced[1] !== 3;
});

// `%TypedArray%.prototype.toSpliced` method
// https://tc39.es/proposal-change-array-by-copy/#sec-%typedarray%.prototype.toSpliced
exportTypedArrayMethod('toSpliced', function toSpliced(start, deleteCount /* , ...items */) {
  var O = aTypedArray(this);
  var C = getTypedArrayConstructor(O);
  var len = lengthOfArrayLike(O);
  var actualStart = toAbsoluteIndex(start, len);
  var argumentsLength = arguments.length;
  var k = 0;
  var insertCount, actualDeleteCount, thisIsBigIntArray, convertedItems, value, newLen, A;
  if (argumentsLength === 0) {
    insertCount = actualDeleteCount = 0;
  } else if (argumentsLength === 1) {
    insertCount = 0;
    actualDeleteCount = len - actualStart;
  } else {
    actualDeleteCount = min(max(toIntegerOrInfinity(deleteCount), 0), len - actualStart);
    insertCount = argumentsLength - 2;
    if (insertCount) {
      convertedItems = new C(insertCount);
      thisIsBigIntArray = isBigIntArray(convertedItems);
      for (var i = 2; i < argumentsLength; i++) {
        value = arguments[i];
        // FF30- typed arrays doesn't properly convert objects to typed array values
        convertedItems[i - 2] = thisIsBigIntArray ? toBigInt(value) : +value;
      }
    }
  }
  newLen = len + insertCount - actualDeleteCount;
  A = new C(newLen);

  for (; k < actualStart; k++) A[k] = O[k];
  for (; k < actualStart + insertCount; k++) A[k] = convertedItems[k - actualStart];
  for (; k < newLen; k++) A[k] = O[k + actualDeleteCount - insertCount];

  return A;
}, !PROPER_ORDER);