esnext.number.from-string.js 2.6 KB

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  1. 'use strict';
  2. var $ = require('../internals/export');
  3. var uncurryThis = require('../internals/function-uncurry-this');
  4. var toIntegerOrInfinity = require('../internals/to-integer-or-infinity');
  5. var INVALID_NUMBER_REPRESENTATION = 'Invalid number representation';
  6. var INVALID_RADIX = 'Invalid radix';
  7. var $RangeError = RangeError;
  8. var $SyntaxError = SyntaxError;
  9. var $TypeError = TypeError;
  10. var $parseInt = parseInt;
  11. var pow = Math.pow;
  12. var valid = /^[0-9a-z]+(\.[0-9a-z]+)?$/;
  13. var charAt = uncurryThis(''.charAt);
  14. var charCodeAt = uncurryThis(''.charCodeAt);
  15. var exec = uncurryThis(valid.exec);
  16. var numberToString = uncurryThis(1.1.toString);
  17. var stringSlice = uncurryThis(''.slice);
  18. var split = uncurryThis(''.split);
  19. var validDigitForRadix = function (string, R) {
  20. for (var i = 0; i < string.length; i++) {
  21. var code = charCodeAt(string, i);
  22. // '.' is allowed
  23. if (code === 0x2E) continue;
  24. // '0'-'9' - digit value 0-9
  25. if (code >= 0x30 && code <= 0x39) {
  26. if (code - 0x30 >= R) return false;
  27. // 'a'-'z' - digit value 10-35
  28. } else if (code >= 0x61 && code <= 0x7A) {
  29. if (code - 0x61 + 10 >= R) return false;
  30. } else return false;
  31. }
  32. return true;
  33. };
  34. // `Number.fromString` method
  35. // https://github.com/tc39/proposal-number-fromstring
  36. $({ target: 'Number', stat: true, forced: true }, {
  37. fromString: function fromString(string, radix) {
  38. var sign = 1;
  39. if (typeof string != 'string') throw new $TypeError(INVALID_NUMBER_REPRESENTATION);
  40. if (!string.length) throw new $SyntaxError(INVALID_NUMBER_REPRESENTATION);
  41. if (charAt(string, 0) === '-') {
  42. sign = -1;
  43. string = stringSlice(string, 1);
  44. if (!string.length) throw new $SyntaxError(INVALID_NUMBER_REPRESENTATION);
  45. }
  46. var R = radix === undefined ? 10 : toIntegerOrInfinity(radix);
  47. if (R < 2 || R > 36) throw new $RangeError(INVALID_RADIX);
  48. if (!exec(valid, string) || !validDigitForRadix(string, R)) throw new $SyntaxError(INVALID_NUMBER_REPRESENTATION);
  49. var parts = split(string, '.');
  50. var mathNum = $parseInt(parts[0], R);
  51. if (parts.length > 1) mathNum += $parseInt(parts[1], R) / pow(R, parts[1].length);
  52. if (R === 10) {
  53. var compareString = string;
  54. if (parts.length > 1) {
  55. var fraction = parts[1];
  56. while (fraction.length && charAt(fraction, fraction.length - 1) === '0') {
  57. fraction = stringSlice(fraction, 0, -1);
  58. }
  59. compareString = fraction.length ? parts[0] + '.' + fraction : parts[0];
  60. }
  61. if (numberToString(mathNum, R) !== compareString) throw new $SyntaxError(INVALID_NUMBER_REPRESENTATION);
  62. }
  63. return sign * mathNum;
  64. }
  65. });