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how to check undefined in react native?

Infinitbility
React Native
August 6th, 2022 · 1 min read
how to check undefined in react native?

Hi Friends 👋,

Welcome To Infinitbility! ❤️

To check or handle undefined in react native, use the if statement it will go inside in if statement if the value is not undefined.

Basically, If the statement will handle all your false values like 0, false, "", undefined, etc.

1let value = undefined;
2
3if(value){
4 console.log("value have some data")
5} else {
6 console.log("value is undefined")
7}

Today, I’m going to show you How do I check or handle undefined in react native, as above mentioned, I’m going to use the if statement to check value is undefined or has some data.

Let’s start today’s tutorial how do you check or handle undefined in react native?

React native check undefined example

Here, we will take an example of two states one state has some data and another have an undefined value, we will check both state console for the undefined state name.

1import React, { useState, useEffect } from "react";
2export default function App() {
3 const [str1] = useState("Infinitbility");
4 const [str2] = useState(undefined);
5
6 useEffect(() => {
7 if (str1) {
8 console.log("str1 have data");
9 } else {
10 console.log("str1 is undefined");
11 }
12
13 if (str2) {
14 console.log("str2 have data");
15 } else {
16 console.log("str2 is undefined");
17 }
18 }, []);
19
20 return (
21 <div className="App">
22 <p>{str1 ? "str1 have data" : "str1 is undefined"}</p>
23 <p>{str2 ? "str2 have data" : "str2 is undefined"}</p>
24 </div>
25 );
26}

In the above example, I have also put the example check undefined in render code here to check undefined we can use the ternary operator.

I hope it helps you, All the best 👍.

React Native, check or handle undefined example
React Native, check or handle undefined example

Try it yourself

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