ES6结合正则判断js数据类型

Posted 2020-12-22 James的博客园

ES5：(有重复问题)

typeof 1           ---> ‘number‘
typeof ‘hello‘     ---> ‘string‘
typeof alert       ---> ‘function‘
typeof [1,2,3]     ---> ‘object‘
typeof {a:1,b:2}   ---> ‘object‘
typeof null        ---> ‘object‘
typeof NaN         ---> ‘number‘
typeof undefined   ---> ‘undefined‘
typeof Symbol()    ---> ‘symbol‘

ES6: （修补了问题）

console.log(Object.prototype.toString.call("hello"));//[object String]
console.log(Object.prototype.toString.call(123));//[object Number]
console.log(Object.prototype.toString.call(true));//[object Boolean]
console.log(Object.prototype.toString.call(undefined));//[object Undefined]
console.log(Object.prototype.toString.call(null));//[object Null]
console.log(Object.prototype.toString.call({name: "jerry"}));//[object Object]
console.log(Object.prototype.toString.call(function(){}));//[object Function]
console.log(Object.prototype.toString.call([]));//[object Array]
console.log(Object.prototype.toString.call(new Date));//[object Date]
console.log(Object.prototype.toString.call(/d/));//[object RegExp]
function foo(){}
console.log(Object.prototype.toString.call(new foo()));//[object Object]

 

最后ES6结合正则的方式，使用最方便：

const isType = type =>(/^[objects(.*)]$/.exec(Object.prototype.toString.call(type)))[1];
isType({}) // ‘Object‘
isType([]) // ‘Array‘

注意首字母是大写

 

 

 

 

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