当前位置:网站首页>[js] 技巧 简化if 判空
[js] 技巧 简化if 判空
2022-07-05 15:49:00 【533_】
1. 简化条件表达式
// 太长的逻辑表达式
if (x === 'abc' || x === 'def' || x === 'ghi' || x ==='jkl') {
//其他逻辑
}
// 简写
if (['abc', 'def', 'ghi', 'jkl'].includes(x)) {
//其他逻辑
}
简化 if … else
// 新手的写法
let test= boolean;
if (x > 100) {
test = true;
} else {
test = false;
}
// 简写表达式
let test = (x > 10) ? true : false;
// 更直接的
let test = x > 10;
console.log(test);
判空并赋默认值
if (first !== null || first !== undefined || first !== '') {
let second = first;
}
// 简写
let second = first || '';
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