JavaScripts浮点数计算问题

JS数学运算精度问题

最近项目上JS做加减乘除这类的运算出现了精度不匹配的问题:

例如：

• 0.1+0.2
• ->0.30000000000000004
• 0.3-0.2
• ->0.09999999999999998
• 0.3*2
• ->0.6
• 0.3*0.2
• 0.06
• 0.3/3
• ->0.09999999999999999

Mathjs这个JS库可以解决这类问题：官网链接

以下是详细的步骤：

1. 终端执行npm install mathjs

2. 然后引入所有的库
   import * as math from "mathjs";

3. 组件代码如下：

<template>
  <article class="article">
    <h3 class="title">{{ title }}</h3>
  </article>
</template>
<script>
import * as math from "mathjs";
export default {
  data() {
    return {
      title: "Hello World",
    };
  },
  methods: {
   
      oldNumberTest() {
      console.log("===oldNumberTest===");
      console.log("0.1+0.2=",0.1+0.2);
      console.log("0.89-0.2=",0.89-0.2);
      console.log("0.1*0.2=",0.1*0.2);
      console.log("0.3/3=",0.3/3);
    },
    mathNumber(){
      console.log("===mathNumber===");
      let sum=this.convert(math.add(math.fraction(0.1), math.fraction(0.2)))
      console.log("math.add(0.1,0.2)=",sum);
       
    },
    convert(value) {
      return(math.format(value, { fraction: "decimal" }));
    },
  },
  created() {
    this.oldNumberTest();
    this.mathNumber();
  },
};
</script>

<style lang="stylus" scoped>
.article
  .title
    border-bottom: solid 3px rgba(red, .2)
</style>

具体的函数请参阅官网