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<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>数值扩展</title>
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<body>
<script>
//0. Number.EPSILON 是 JavaScript 表示的最小精度
//EPSILON 属性的值接近于 2.2204460492503130808472633361816E-16
function equal(a, b){
if(Math.abs(a-b) < Number.EPSILON){
return true;
}else{
return false;
}
}
console.log(0.1 + 0.2 === 0.3);
console.log(equal(0.1 + 0.2, 0.3))
//1. 二进制和八进制
let b = 0b1010;
let o = 0o777;
let d = 100;
let x = 0xff;
console.log(x);
//2. Number.isFinite 检测一个数值是否为有限数
console.log(Number.isFinite(100));
console.log(Number.isFinite(100/0));
console.log(Number.isFinite(Infinity));
//3. Number.isNaN 检测一个数值是否为 NaN
console.log(Number.isNaN(123));
//4. Number.parseInt Number.parseFloat字符串转整数
console.log(Number.parseInt('5211314love'));
console.log(Number.parseFloat('3.1415926神奇'));
//5. Number.isInteger 判断一个数是否为整数
console.log(Number.isInteger(5));
console.log(Number.isInteger(2.5));
//6. Math.trunc 将数字的小数部分抹掉
console.log(Math.trunc(3.5));
//7. Math.sign 判断一个数到底为正数 负数 还是零
console.log(Math.sign(100));
console.log(Math.sign(0));
console.log(Math.sign(-20000));
</script>
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标签：ES6,console,log,扩展,Number,数值,sign,let,Math From： https://www.cnblogs.com/anjingdian/p/16908638.html