1 | 'use strict';
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2 | var $ = require('../internals/export');
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3 | var toInteger = require('../internals/to-integer');
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4 | var thisNumberValue = require('../internals/this-number-value');
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5 | var repeat = require('../internals/string-repeat');
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6 | var fails = require('../internals/fails');
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7 |
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8 | var nativeToFixed = 1.0.toFixed;
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9 | var floor = Math.floor;
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10 |
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11 | var pow = function (x, n, acc) {
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12 | return n === 0 ? acc : n % 2 === 1 ? pow(x, n - 1, acc * x) : pow(x * x, n / 2, acc);
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13 | };
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14 |
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15 | var log = function (x) {
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16 | var n = 0;
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17 | var x2 = x;
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18 | while (x2 >= 4096) {
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19 | n += 12;
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20 | x2 /= 4096;
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21 | }
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22 | while (x2 >= 2) {
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23 | n += 1;
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24 | x2 /= 2;
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25 | } return n;
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26 | };
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27 |
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28 | var FORCED = nativeToFixed && (
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29 | 0.00008.toFixed(3) !== '0.000' ||
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30 | 0.9.toFixed(0) !== '1' ||
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31 | 1.255.toFixed(2) !== '1.25' ||
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32 | 1000000000000000128.0.toFixed(0) !== '1000000000000000128'
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33 | ) || !fails(function () {
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34 |
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35 | nativeToFixed.call({});
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36 | });
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37 |
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38 |
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39 |
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40 | $({ target: 'Number', proto: true, forced: FORCED }, {
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41 |
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42 | toFixed: function toFixed(fractionDigits) {
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43 | var number = thisNumberValue(this);
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44 | var fractDigits = toInteger(fractionDigits);
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45 | var data = [0, 0, 0, 0, 0, 0];
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46 | var sign = '';
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47 | var result = '0';
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48 | var e, z, j, k;
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49 |
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50 | var multiply = function (n, c) {
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51 | var index = -1;
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52 | var c2 = c;
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53 | while (++index < 6) {
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54 | c2 += n * data[index];
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55 | data[index] = c2 % 1e7;
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56 | c2 = floor(c2 / 1e7);
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57 | }
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58 | };
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59 |
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60 | var divide = function (n) {
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61 | var index = 6;
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62 | var c = 0;
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63 | while (--index >= 0) {
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64 | c += data[index];
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65 | data[index] = floor(c / n);
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66 | c = (c % n) * 1e7;
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67 | }
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68 | };
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69 |
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70 | var dataToString = function () {
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71 | var index = 6;
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72 | var s = '';
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73 | while (--index >= 0) {
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74 | if (s !== '' || index === 0 || data[index] !== 0) {
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75 | var t = String(data[index]);
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76 | s = s === '' ? t : s + repeat.call('0', 7 - t.length) + t;
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77 | }
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78 | } return s;
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79 | };
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80 |
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81 | if (fractDigits < 0 || fractDigits > 20) throw RangeError('Incorrect fraction digits');
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82 |
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83 | if (number != number) return 'NaN';
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84 | if (number <= -1e21 || number >= 1e21) return String(number);
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85 | if (number < 0) {
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86 | sign = '-';
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87 | number = -number;
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88 | }
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89 | if (number > 1e-21) {
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90 | e = log(number * pow(2, 69, 1)) - 69;
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91 | z = e < 0 ? number * pow(2, -e, 1) : number / pow(2, e, 1);
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92 | z *= 0x10000000000000;
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93 | e = 52 - e;
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94 | if (e > 0) {
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95 | multiply(0, z);
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96 | j = fractDigits;
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97 | while (j >= 7) {
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98 | multiply(1e7, 0);
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99 | j -= 7;
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100 | }
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101 | multiply(pow(10, j, 1), 0);
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102 | j = e - 1;
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103 | while (j >= 23) {
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104 | divide(1 << 23);
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105 | j -= 23;
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106 | }
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107 | divide(1 << j);
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108 | multiply(1, 1);
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109 | divide(2);
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110 | result = dataToString();
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111 | } else {
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112 | multiply(0, z);
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113 | multiply(1 << -e, 0);
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114 | result = dataToString() + repeat.call('0', fractDigits);
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115 | }
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116 | }
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117 | if (fractDigits > 0) {
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118 | k = result.length;
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119 | result = sign + (k <= fractDigits
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120 | ? '0.' + repeat.call('0', fractDigits - k) + result
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121 | : result.slice(0, k - fractDigits) + '.' + result.slice(k - fractDigits));
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122 | } else {
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123 | result = sign + result;
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124 | } return result;
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125 | }
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126 | });
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