GroupBy.js 2.4 KB

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  1. 'use strict';
  2. var $TypeError = require('es-errors/type');
  3. var isNegativeZero = require('math-intrinsics/isNegativeZero');
  4. var MAX_SAFE_INTEGER = require('math-intrinsics/constants/maxSafeInteger');
  5. var AddValueToKeyedGroup = require('./AddValueToKeyedGroup');
  6. var Call = require('./Call');
  7. var GetIterator = require('./GetIterator');
  8. var IsCallable = require('./IsCallable');
  9. var IteratorClose = require('./IteratorClose');
  10. var IteratorStep = require('./IteratorStep');
  11. var IteratorValue = require('./IteratorValue');
  12. var RequireObjectCoercible = require('./RequireObjectCoercible');
  13. var ThrowCompletion = require('./ThrowCompletion');
  14. var ToPropertyKey = require('./ToPropertyKey');
  15. // https://262.ecma-international.org/15.0/#sec-groupby
  16. module.exports = function GroupBy(items, callbackfn, keyCoercion) {
  17. if (keyCoercion !== 'PROPERTY' && keyCoercion !== 'ZERO') {
  18. throw new $TypeError('Assertion failed: `keyCoercion` must be `"PROPERTY"` or `"ZERO"`');
  19. }
  20. RequireObjectCoercible(items); // step 1
  21. if (!IsCallable(callbackfn)) {
  22. throw new $TypeError('callbackfn must be callable'); // step 2
  23. }
  24. var groups = []; // step 3
  25. var iteratorRecord = GetIterator(items, 'SYNC'); // step 4
  26. var k = 0; // step 5
  27. // eslint-disable-next-line no-constant-condition
  28. while (true) { // step 6
  29. if (k >= MAX_SAFE_INTEGER) { // step 6.a
  30. var error = ThrowCompletion(new $TypeError('k must be less than 2 ** 53 - 1')); // step 6.a.i
  31. IteratorClose(iteratorRecord, error); // step 6.a.ii
  32. return void undefined;
  33. }
  34. var next = IteratorStep(iteratorRecord); // step 6.b
  35. if (!next) { // step 6.c
  36. return groups; // step 6.c.i
  37. }
  38. var value = IteratorValue(next); // step 6.dv
  39. var key;
  40. try {
  41. key = Call(callbackfn, undefined, [value, k]); // step 6.e
  42. } catch (e) {
  43. IteratorClose(iteratorRecord, ThrowCompletion(e)); // step 6.f
  44. return void undefined;
  45. }
  46. if (keyCoercion === 'PROPERTY') { // step 6.g
  47. try {
  48. key = ToPropertyKey(key); // step 6.g.i
  49. } catch (e) {
  50. IteratorClose(iteratorRecord, ThrowCompletion(e)); // step 6.g.ii
  51. return void undefined;
  52. }
  53. } else { // step 6.h
  54. if (keyCoercion !== 'ZERO') {
  55. throw new $TypeError('keyCoercion must be ~PROPERTY~ or ~ZERO~'); // step 6.h.i
  56. }
  57. if (isNegativeZero(key)) {
  58. key = +0; // step 6.h.ii
  59. }
  60. }
  61. AddValueToKeyedGroup(groups, key, value); // step 6.i
  62. k += 1; // step 6.j
  63. }
  64. };