判定是否为非负整数

如何高效判定是非负整数,类型是number

下面是群里的一些记录:

var num = -4;

( n| 0 ) === n //ssddi456  ng

( n >= 0 ) && ( n % 1 == 0 );// 司徒正美 ng

var n ="33"
parseInt(n) > 0 && n == Math.round(n)// 烦茄 ng

typeof n == 'number' && n >0 && n == Math.round(n) //烦茄 ok

 n === n >> 0 && n >= 0 // im007boy ok
 
var n = "22"
console.log((~n | 0) == -Math.abs(-n -1)) // 烦茄 ng


( 0x80000000 & num ) //BruceWolf ng 这是C语言的hack

~~i === i && i >= 0 //刺猬 ok

var num = -9
parseInt( num )=== num && num > 0 //BruceWolf  ok

原文地址:https://www.cnblogs.com/rubylouvre/p/2438692.html