ES6开发技巧：Number Skill数值技巧

Number Skill

取整

代替正数的Math.floor()，代替负数的Math.ceil()

const num1 = ~~ 1.69;
const num2 = 1.69 | 0;
const num3 = 1.69 >> 0;
// num1 num2 num3 => 1 1 1
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补零

const FillZero = (num, len) => num.toString().padStart(len, "0");
const num = FillZero(169, 5);
// num => "00169"
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转数值

只对null、""、false、数值字符串有效

const num1 = +null;
const num2 = +"";
const num3 = +false;
const num4 = +"169";
// num1 num2 num3 num4 => 0 0 0 169
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时间戳

const timestamp = +new Date("2019-02-14");
// timestamp => 1550102400000
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精确小数

const RoundNum = (num, decimal) => Math.round(num * 10 ** decimal) / 10 ** decimal;
const num = RoundNum(1.69, 1);
// num => 1.7
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判断奇偶

const OddEven = num => !!(num & 1) ? "odd" : "even";
const num = OddEven(2);
// num => "even"
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取最小最大值

const arr = [0, 1, 2];
const min = Math.min(...arr);
const max = Math.max(...arr);
// min max => 0 2
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生成范围随机数

const RandomNum = (min, max) => Math.floor(Math.random() * (max - min + 1)) + min;
const num = RandomNum(1, 10);