if简洁干净
if判断不等于(多个)的情况:|| ' '
<script type="text/javascript"> const test1 = 'wowowowowo' if (test1 !==null | test1 !==undefined | test1 !== '') { var test2 = test1 } //直接js这样就可以了 let test3 = test1 || '' console.log(test2)//wowowowowo console.log(test3)//wowowowowo </script>
if判断之后赋值的情况:三元替换
<script type="text/javascript"> let x = 1 if (x > 10) { test = true; } else { test = false; } let test = (x > 10) ? true : false; console.log(test) //大于10返回true,不是false </script>
if判断等于(多个)的情况:includes
if (x === 'abc' || x === 'def' || x === 'ghi' || x ==='jkl') { //logic } if (['abc', 'def', 'ghi', 'jkl'].includes(x)) { //logic }
&&简化if
<script type="text/javascript"> let test = 11 if(test>10){ console.log(10)//10 } test > 10 && console.log(10)//10 test大于10会执行&&右边的方法 </script>
操作符
test1 = test1 + 1; test2 = test2 - 1; test3 = test3 * 20; test1++; test2--; test3 *= 20
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