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- 'use strict';
- var $ = require('../internals/export');
- var uncurryThis = require('../internals/function-uncurry-this');
- var toIntegerOrInfinity = require('../internals/to-integer-or-infinity');
- var thisNumberValue = require('../internals/this-number-value');
- var $repeat = require('../internals/string-repeat');
- var fails = require('../internals/fails');
-
- var $RangeError = RangeError;
- var $String = String;
- var floor = Math.floor;
- var repeat = uncurryThis($repeat);
- var stringSlice = uncurryThis(''.slice);
- var nativeToFixed = uncurryThis(1.0.toFixed);
-
- var pow = function (x, n, acc) {
- return n === 0 ? acc : n % 2 === 1 ? pow(x, n - 1, acc * x) : pow(x * x, n / 2, acc);
- };
-
- var log = function (x) {
- var n = 0;
- var x2 = x;
- while (x2 >= 4096) {
- n += 12;
- x2 /= 4096;
- }
- while (x2 >= 2) {
- n += 1;
- x2 /= 2;
- } return n;
- };
-
- var multiply = function (data, n, c) {
- var index = -1;
- var c2 = c;
- while (++index < 6) {
- c2 += n * data[index];
- data[index] = c2 % 1e7;
- c2 = floor(c2 / 1e7);
- }
- };
-
- var divide = function (data, n) {
- var index = 6;
- var c = 0;
- while (--index >= 0) {
- c += data[index];
- data[index] = floor(c / n);
- c = (c % n) * 1e7;
- }
- };
-
- var dataToString = function (data) {
- var index = 6;
- var s = '';
- while (--index >= 0) {
- if (s !== '' || index === 0 || data[index] !== 0) {
- var t = $String(data[index]);
- s = s === '' ? t : s + repeat('0', 7 - t.length) + t;
- }
- } return s;
- };
-
- var FORCED = fails(function () {
- return nativeToFixed(0.00008, 3) !== '0.000' ||
- nativeToFixed(0.9, 0) !== '1' ||
- nativeToFixed(1.255, 2) !== '1.25' ||
- nativeToFixed(1000000000000000128.0, 0) !== '1000000000000000128';
- }) || !fails(function () {
- // V8 ~ Android 4.3-
- nativeToFixed({});
- });
-
- // `Number.prototype.toFixed` method
- // https://tc39.es/ecma262/#sec-number.prototype.tofixed
- $({ target: 'Number', proto: true, forced: FORCED }, {
- toFixed: function toFixed(fractionDigits) {
- var number = thisNumberValue(this);
- var fractDigits = toIntegerOrInfinity(fractionDigits);
- var data = [0, 0, 0, 0, 0, 0];
- var sign = '';
- var result = '0';
- var e, z, j, k;
-
- // TODO: ES2018 increased the maximum number of fraction digits to 100, need to improve the implementation
- if (fractDigits < 0 || fractDigits > 20) throw new $RangeError('Incorrect fraction digits');
- // eslint-disable-next-line no-self-compare -- NaN check
- if (number !== number) return 'NaN';
- if (number <= -1e21 || number >= 1e21) return $String(number);
- if (number < 0) {
- sign = '-';
- number = -number;
- }
- if (number > 1e-21) {
- e = log(number * pow(2, 69, 1)) - 69;
- z = e < 0 ? number * pow(2, -e, 1) : number / pow(2, e, 1);
- z *= 0x10000000000000;
- e = 52 - e;
- if (e > 0) {
- multiply(data, 0, z);
- j = fractDigits;
- while (j >= 7) {
- multiply(data, 1e7, 0);
- j -= 7;
- }
- multiply(data, pow(10, j, 1), 0);
- j = e - 1;
- while (j >= 23) {
- divide(data, 1 << 23);
- j -= 23;
- }
- divide(data, 1 << j);
- multiply(data, 1, 1);
- divide(data, 2);
- result = dataToString(data);
- } else {
- multiply(data, 0, z);
- multiply(data, 1 << -e, 0);
- result = dataToString(data) + repeat('0', fractDigits);
- }
- }
- if (fractDigits > 0) {
- k = result.length;
- result = sign + (k <= fractDigits
- ? '0.' + repeat('0', fractDigits - k) + result
- : stringSlice(result, 0, k - fractDigits) + '.' + stringSlice(result, k - fractDigits));
- } else {
- result = sign + result;
- } return result;
- }
- });
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