How to check if a key exists in an object in javascript

2018-06-08 19:53:22

This question already has an answer here:

Checking if a key exists in a JavaScript object? 16 answers

Use the hasOwnProperty call

if (!obj.hasOwnProperty(key)) {

}

https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/hasOwnProperty

你可以这样做：

var key = 'key1';
if (!('key1' in obj)) {
    ....
} 
// or
if (!(key in obj)) {

}

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