typeof 和 instanceof

2024-02-08 17:39:58

1 typeof

console.log(typeof 123) // number
console.log(typeof 'abc') // string
console.log(typeof true) // boolean
console.log(typeof undefined) // undefined
console.log(typeof null) // object
console.log(typeof {a: 1}) // object
console.log(typeof [1,2,3]) // object
console.log(typeof function(){ let a = 1}) // function

2 instanceof

判断该对象是谁的实例

console.log([1 ,2 , 3] instanceof Array) // true