作用 :就是將一些變量轉(zhuǎn)化為Number(數(shù)字)類(lèi)型的!!!
數(shù)字類(lèi)型的字符串可以轉(zhuǎn)化為純數(shù)字
let a = '111111';
console.log( ~~a ); //輸出111111
字符串中帶了其他字母雇卷,符號(hào),都會(huì)輸出 Number類(lèi)型的0
let a = 'aaa';
console.log( ~~a ); //輸出0
boolen類(lèi)型的,如果為true則輸出1矢棚,false輸出0;
let hello = 1 == 1;
console.log( ~~hello );//輸出1
特殊類(lèi)型,轉(zhuǎn)化為Boolean是true的輸出1,轉(zhuǎn)化為boolean是false的輸出0全度;
let hyb = undefined;
console.log( ~~hyb );//輸出0
let a = !undefined;
console.log( ~~a );//輸出1
let b = 斥滤!null;
console.log( ~~b );//輸出1
let c = 将鸵!NaN;
console.log( ~~c );//輸出1