How to set Error.code property in Node.js v12.x ?
Last Updated :
04 Aug, 2022
Setting setError.code property in Node.js v12.x or above is a bit complex process, but In this article, you will learn to do this in a very easy way.
Problem Statement: Sometimes we want to set the error code manually, we want to show our own error code instead of a pre-built error code when throwing an error.
Approach: We have to extend the prebuilt Error class and set code property according to our needs. Inside inherit class, we have to create a constructor which is used to set the error message.
class manualError extends Error {
constructor (message) {
super(message);
this.code = 'ERRORGEEK';
}
}
We can set an error message by creating an object of the child class with an error message as a parameter.
let err = new manualError('opps!');
Example 1: Let’s see how to set an Error.code property in Node.js v12.x through this example. Follow the below steps:
Step 1: Create and Open a project folder inside a code editor.
Step 2: Locate the project folder inside the terminal.
Step 3: Create a file app.js either manually or by typing the command
touch app.js
Step 4: Open the file inside the code editor.
Step 5: Write the following code:
Javascript
class manualError extends Error {
constructor (message) {
super (message);
this .code = 'ERRORGEEK' ;
}
}
let err = new manualError( 'opps!' );
console.log(err);
|
Step 6: Inside the terminal type the command to run your script.
node app.js
Output:
Example 2: This is another example that shows how to set an Error.code property in Node.js v12.x through this example. Follow the below steps:
Step 1: Create and Open a project folder inside a code editor.
Step 2: Locate the project folder inside the terminal.
Step 3: Create a file app.js either manually or by typing the command
touch app.js
Step 4: Open the file inside the code editor.
Step 5: Write the following code:
Javascript
class manualError extends Error {
constructor (message) {
super (message);
this .code = 'ERRORGEEK' ;
}
}
function checkEquality (a, b) {
if (a === b) {
console.log( 'numbers are equal' );
} else {
let err = new manualError( 'numbers are not equal' );
throw err;
}
}
checkEquality(12, 14);
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Step 6: Inside the terminal type the command to run your script.
node app.js
Output:
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