JS

目录

• 前言
  • JS - 浮点数计算不精确
  • 解决方案
  • 结果验证

前言

js浮点数的计算存在精度不准的问题，解决方案：用整数与整数的加减乘除运算来规避该问题。

JS - 浮点数计算不精确

let [num1,num2] = [0.1, 0.2];

console.log(num1 + num2); // 0.30000000000000004
console.log(num1 - num2); // -0.1
console.log(num1 * num2); // 0.020000000000000004
console.log(num1 / num2); // 0.5

解决方案

• number.js

/**
 * 加 +
 * @param num1
 * @param num2
 * @returns {number}
 */
function accAddition(num1, num2) {
    const num1Digits = (num1.toString().split('.')[1] || '').length;
    const num2Digits = (num2.toString().split('.')[1] || '').length;
    const baseNum = Math.pow(10, Math.max(num1Digits, num2Digits));
    return (Math.round(num1 * baseNum) + Math.round(num2 * baseNum)) / baseNum;
}

/**
 * 减 -
 * @param num1
 * @param num2
 * @returns {number}
 */
function accSubtract(num1, num2) {
    const num1Digits = (num1.toString().split('.')[1] || '').length;
    const num2Digits = (num2.toString().split('.')[1] || '').length;
    const baseNum = Math.pow(10, Math.max(num1Digits, num2Digits));
    return (Math.round(num1 * baseNum) - Math.round(num2 * baseNum)) / baseNum;
}

/**
 * 乘 *
 * @param num1
 * @param num2
 * @returns {number}
 */
function accMultiply(num1, num2) {
    const num1Digits = (num1.toString().split('.')[1] || '').length;
    const num2Digits = (num2.toString().split('.')[1] || '').length;
    const baseNum = Math.pow(10, Math.max(num1Digits, num2Digits));
    return (Math.round(num1 * baseNum) * Math.round(num2 * baseNum)) / baseNum / baseNum;
}

/**
 * 除 /
 * @param num1
 * @param num2
 * @returns {number}
 */
function accDivision(num1, num2) {
    const num1Digits = (num1.toString().split('.')[1] || '').length;
    const num2Digits = (num2.toString().split('.')[1] || '').length;
    const baseNum = Math.pow(10, Math.max(num1Digits, num2Digits));
    return (Math.round(num1 * baseNum) / Math.round(num2 * baseNum));
}

export {
    accAddition,
    accMultiply,
    accSubtract,
    accDivision
}

结果验证

import {accAddition, accSubtract, accMultiply, accDivision} from "@/utils/number";

let [num1,num2] = [0.1, 0.2];

console.log(accAddition(num1, num2)); // 0.3
console.log(accSubtract(num1, num2)); // -0.1
console.log(accMultiply(num1, num2)); // 0.02
console.log(accDivision(num1, num2)); // 0.5

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