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Editor to share with you how to achieve js optional chain, I believe that most people do not know much about it, so share this article for your reference, I hope you can learn a lot after reading this article, let's go to understand it!

Optional chain?.

Do we often encounter such an error: TypeError: Cannot read property 'foo' of null. This is an annoying problem for every Yi developer. The introduction of optional chain is to solve this problem. Let's take a look:

Const book = {id:1, title: 'Title', author: null}; / / normally, you would do this: console.log (book.author.age) / / throws errorconsole.log (book.author & & book.author.age); / / null// uses optional chain console.log (book.author?.age); / / undefined// or deep optional chain console.log (book.author?.address?.city); / / undefined

You can also use the following function optional chain:

Const person = {firstName: 'front-end', lastName: 'this.lastName', printName: function () {return `${this.firstName} ${this.lastName}`;},}; console.log (person.printName ()); / / 'front-end smart' console.log (persone.doesNotExist?. ()); / / undefined above is all the content of the article "how to implement optional chains in js". Thank you for reading! I believe we all have a certain understanding, hope to share the content to help you, if you want to learn more knowledge, welcome to follow the industry information channel!

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