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bignumber.js库，解决前端小数精度问题

news 2025/7/23 11:54:34

bignumber.js 是一个 JavaScript 库，用于执行任意精度的十进制运算，特别适合处理大数字和需要高精度运算的情况。以下是一些 bignumber.js 库中的常用方法及其简要解释：

初始化

首先，你需要安装 bignumber.js 库：

npm install bignumber.js

然后在你的代码中引入：

const BigNumber = require('bignumber.js');

如果是ts中引入可以使用import

import BigNumber from 'bignumber.js';

常用方法

1. 创建一个 BigNumber 实例

const x = new BigNumber(123.456); // 从数字创建
const y = new BigNumber('123456.789e-3'); // 从字符串创建
const z = new BigNumber(x); // 从另一个 BigNumber 实例创建

2. 加法

const a = new BigNumber(0.1);
const b = new BigNumber(0.2);
const sum = a.plus(b); // 0.3
console.log(sum.toString()); // "0.3"

3. 减法

const difference = a.minus(b);
console.log(difference.toString()); // "-0.1"

4. 乘法

const product = a.times(b);
console.log(product.toString()); // "0.02"

5. 除法

const quotient = a.div(b);
console.log(quotient.toString()); // "0.5"

6. 取模

const remainder = a.mod(b);
console.log(remainder.toString()); // "0.1"

7. 幂运算

const pow = a.pow(2);
console.log(pow.toString()); // "0.01"

8. 平方根

const sqrt = a.sqrt();
console.log(sqrt.toString()); // "0.31622776601683793319988935444327"

9. 比较

const a = new BigNumber(3);
const b = new BigNumber(4);console.log(a.isGreaterThan(b)); // false
console.log(a.isLessThan(b)); // true
console.log(a.isEqualTo(b)); // false

10. 格式化输出

const a = new BigNumber(12345.6789);console.log(a.toFixed(2)); // "12345.68"
console.log(a.toExponential(2)); // "1.23e+4"
console.log(a.toPrecision(6)); // "12345.7"

11. 取整和取绝对值

const a = new BigNumber(-123.456);console.log(a.integerValue().toString()); // "-123"
console.log(a.absoluteValue().toString()); // "123.456"

12. 配置全局设置

你可以通过 BigNumber.config 来配置一些全局设置，比如精度和舍入模式：

BigNumber.config({ DECIMAL_PLACES: 10, ROUNDING_MODE: BigNumber.ROUND_HALF_UP });

示例总结

通过下面这个示例，你可以了解如何使用以上方法进行一些常见的运算：

const BigNumber = require('bignumber.js');// 创建 BigNumber 实例
const x = new BigNumber(0.1);
const y = new BigNumber(0.2);
// 实际在前端中0.1+0.2 是不等于0.3的，原因是前端的浮点数无法精确的表示小数// 加法
const sum = x.plus(y);
console.log(`Sum: ${sum.toString()}`); // "Sum: 0.3"// 减法
const difference = x.minus(y);
console.log(`Difference: ${difference.toString()}`); // "Difference: -0.1"// 乘法
const product = x.times(y);
console.log(`Product: ${product.toString()}`); // "Product: 0.02"// 除法
const quotient = x.div(y);
console.log(`Quotient: ${quotient.toString()}`); // "Quotient: 0.5"// 幂运算
const pow = x.pow(2);
console.log(`Power: ${pow.toString()}`); // "Power: 0.01"// 平方根
const sqrt = x.sqrt();
console.log(`Square Root: ${sqrt.toString()}`); // "Square Root: 0.31622776601683793319988935444327"// 比较
console.log(`Is x greater than y? ${x.isGreaterThan(y)}`); // false
console.log(`Is x less than y? ${x.isLessThan(y)}`); // true
console.log(`Is x equal to y? ${x.isEqualTo(y)}`); // false// 格式化输出
const a = new BigNumber(12345.6789);
console.log(a.toFixed(2)); // "12345.68"
console.log(a.toExponential(2)); // "1.23e+4"
console.log(a.toPrecision(6)); // "12345.7"