Big.js库解决JavaScript浮点数精度丢失问题详解

0.1 + 0.2 === 0.30000000000000004

19.9 * 100 === 1989.9999999999998

Number(Number(19.9 * 100).toFixed()) === 1990

npm install big.js

import Big from 'big.js';

let x = new Big(0.1)

0.1 + 0.2                  // 0.30000000000000004
x = new Big(0.1)
y = x.plus(0.2).toNumber()            // 0.3
Big(0.7).plus(x).plus(y).toNumber()   // 1.1

0.3 - 0.1                  // 0.19999999999999998
x = new Big(0.3)
x.minus(0.1).toNumber()               // 0.2

0.6 * 3                    // 1.7999999999999998
x = new Big(0.6)
y = x.times(3).toNumber()             // 1.8
Big('7e+500').times(y).toNumber()     // Infinity
Big('7e+500').times(1.8).toString()   // '1.26e+501'

x = new Big(355)
y = new Big(113)
x.div(y).toNumber()                   // 3.14159292035398230088
Big.DP = 2
x.div(y).toNumber()                   // 3.14
x.div(5).toNumber()                   // 71

Math.pow(0.7, 2)           // 0.48999999999999994
x = new Big(0.7)
x.pow(2)                   // '0.49'
Big.DP = 20
Big(3).pow(-2)             // '0.11111111111111111111'
new Big(123.456).pow(1000).toString().length     // 5099
new Big(2).pow(1e+6)       // Time taken (Node.js): 9 minutes 34 secs.