Uses BigInt to make BigFloats
此脚本不应直接安装。它是供其他脚本使用的外部库，要使用该库请加入元指令 // @require https://update.greasyfork.org/scripts/563676/1745082/BigFloat.js
// ==UserScript==
// @name BigFloat
// @namespace -
// @version 1.0.1
// @description Uses BigInt to make BigFloats
// @author NotYou
// @grant none
// @license MIT
// ==/UserScript==
/*
* @typedef IStringifyOptions
* @property {boolean} [trailingZero=true]
* @property {boolean} [headZero=true]
* @property {number} [precision=3] recommended max value is 15. Higher values may result in incorrect result
* @property {boolean} [fixedPointNotation=false] if value is 12.3, precision is 3, but fixedPointNotation is true, then stringified value will be 12.300
*/
/*
* @typedef IToNumberOptions
* @property {number} [precision=3] recommended max value is 15. Higher values may result in incorrect result
*/
/*
* @typedef {number | `${number}` | BigInt | InstanceType<typeof BigFloat>} AcceptableValue
*/
!function() {
'use strict';
/* global BigInt */
class BigFloat {
/*
* @param {AcceptableValue} value
*/
constructor(value) {
const valueData = this._handleValue(value)
if (valueData === null) this._invalidValue(value)
/*
* @type {number}
*/
this._scale = valueData.scale
/*
* @type {number}
*/
this._value = valueData.value
}
/*
* @returns {string | number}
*/
[Symbol.toPrimitive](hint) {
if (hint === 'number') {
return this.toNumber()
}
return this.stringify()
}
/*
* @returns {string}
*/
get [Symbol.toStringTag]() {
return this.constructor.name
}
/*
* Throws an invalid value error. Stringifies value
*
* @param {AcceptableValue} value
* @returns {never}
*/
_invalidValue(value) {
let stringifiedValue = ''
try {
if (!Number.isFinite(value) || Number.isNaN(value) || typeof value === 'function') {
throw void 0
}
stringifiedValue = JSON.stringify(value)
} catch(_) {
stringifiedValue = String(value)
}
throw new Error(`"${stringifiedValue}" is invalid value and cannot be handled`)
}
/**
* Parses float number
*
* @param {number} value (must be float number)
* @returns { { value: string, scale: number } }
*/
_parseFloat(value) {
const parts = String(value).split('.')
return {
value: parts[0] + parts[1],
scale: -parts[1].length
}
}
/**
* Tries to return value as bigint and, also returns its scale
*
* @param {AcceptableValue} value
* @returns { { value: BigInt, scale: number } | null }
*/
_handleValue(value) {
const handleInt = value => {
return {
value: BigInt(value),
scale: 0
}
}
const handleFloat = value => {
const floatData = this._parseFloat(value)
return {
value: BigInt(floatData.value),
scale: floatData.scale
}
}
if (typeof value === 'bigint') {
return {
value,
scale: 0,
}
} else if (typeof value === 'number' && Number.isInteger(value)) { // is integer
return handleInt(value)
} else if (typeof value === 'number') { // is float
return handleFloat(value)
} else if (typeof value === 'string' && !isNaN(value)) { // is stringified number
const number = Number(value)
if (Number.isInteger(number)) {
return handleInt(number)
}
return handleFloat(number)
} else if (value instanceof this.constructor) {
return {
value: value.getRawValue(),
scale: value.getScale()
}
}
return null
}
/*
* Returns the value of the big float as a raw bigint
*
* @returns {bigint}
*/
getRawValue() {
return this._value
}
/*
* Returns the scale of the value
*
* For example, when: `value = 1234` and `scale = -1``
* Then result would be equal to 123.4
*
* @returns {number}
*/
getScale() {
return this._scale
}
/*
* @type {IStringifyOptions}
*/
_defaultStringifyOptions = {
trailingZero: true,
headZero: true,
precision: 3,
fixedPointNotation: false
}
/*
* Stringifies big float
*
* Note: toString is reserved for Symbol.toStringTag method
*
* @param {Optional<IStringifyOptions>} options
* @returns {string}
*/
stringify(options = {}) {
options = Object.assign({}, this._defaultStringifyOptions, options)
const scale = this.getScale()
const raw = this.getRawValue().toString()
if (scale === 0) {
if (!options.trailingZero) return raw
const zeros = options.fixedPointNotation
? options.precision
: 1
return raw + '.' + '0'.repeat(zeros)
}
const leftPart = raw.slice(0, scale)
let rightPart = raw.slice(scale)
rightPart = rightPart.slice(0, options.precision)
if (options.fixedPointNotation) {
rightPart = rightPart.padEnd(options.precision, '0')
}
if (leftPart === '' && options.headZero) {
return '0.' + rightPart
}
return leftPart + '.' + rightPart
}
/*
* @type {IToNumberOptions}
*/
_defaultToNumberOptions = {
precision: 3
}
/*
* Firstly stringfies the number using stringify (with default params) method, and then converts it to number
*
* @param {Optional<IToNumberOptions>} options
* @returns {number}
*/
toNumber(options) {
options = Object.assign({}, this._defaultToNumberOptions, options)
return Number(this.stringify(options))
}
/*
* @param {AcceptableValue} value Value that will be added or subtracted
* @param {-1 | 1} sign zero for minus, one for plus
* @returns {this}
*/
_addOrSubtract(value, sign) {
const valueData = this._handleValue(value)
if (valueData === null) this._invalidValue(value)
let aValue = this._value
let aScale = this._scale
let bValue = valueData.value
let bScale = valueData.scale
if (aScale !== bScale) {
const minScale = Math.min(aScale, bScale)
if (aScale !== minScale) {
aValue *= 10n ** BigInt(aScale - minScale)
}
if (bScale !== minScale) {
bValue *= 10n ** BigInt(bScale - minScale)
}
aScale = minScale
}
this._value = sign === 1 ? aValue + bValue : aValue - bValue
this._scale = aScale
return this
}
/*
* @param {AcceptableValue} value
* @returns {this}
*/
add(value) {
return this._addOrSubtract(value, 1)
}
/*
* @param {AcceptableValue} value
* @returns {this}
*/
subtract(value) {
return this._addOrSubtract(value, -1)
}
/*
* @param {AcceptableValue} value
* @returns {this}
*/
multiply(value) {
const valueData = this._handleValue(value)
if (valueData === null) this._invalidValue(value)
this._value *= valueData.value
this._scale += valueData.scale
return this
}
/*
* @param {AcceptableValue} value
* @param {number} precision
* @returns {this}
*/
divide(value, precision = 3) {
const valueData = this._handleValue(value)
if (valueData === null) this._invalidValue(value)
if (valueData.value === 0n) {
throw new Error('Division by zero')
}
const factor = 10n ** BigInt(precision)
this._value = (this._value * factor) / valueData.value
this._scale = this._scale - valueData.scale - precision
return this
}
}
window.BigFloat = BigFloat
}();