What is the correct way to prevent an error in React when an array of objects is still undefined?-CodePudding

It's common in React that an element is rendered before all its variables are defined, with final rendering being correct. To prevent fatal errors we usually use the ? operator as suggested in the response to Question by coding:

const property1 = object?.property1

rather than:

const property1 = object.property1 or const { property1 } = object

This approach doesn't work when the object is an array of objects, for instance if I want to preempt a fatal error in react while my array is undefined, I can't use:

const property1 = array?[0]?.property1

since it is syntactically incorrect (should it be?), so I am using:

 `const property1 = array && array[0]?.property1`

Is that the correct way?

Daniel Beck corrected an error in my original question, that is now fixed indicating that an alternative way to handle this situation would be:

const uid = array ? array[0].uid : undefined

CodePudding user response：

You can use Array.isArray() method to determine whether the passed value is an Array or not.

Working Demo :

let obj = {
    property1: 'alpha' 
};

const property1 = Array.isArray(obj) ? obj[0]?.property1 : obj.property1;

console.log(property1);

CodePudding user response：

You can try this

const uid = array[0].uid || "";

If your array or uid will undefined it will set empty string in uid variable