An Error class for LMOS for Node.js project
- Error Message & Code
- HTTP-Response Integration
- Chained-Errors Support
- Timestamp
When I wrote my first commercial Node.js project in 2019, I had been struggling to design a general error-handling module with the standard JavaScript Error object.
Because in the widely-used ECMAScript 3, the standard Error object only supports a text error message. Meanwhile in a real world server-side environment, handling an error usually means:
- Identifying the error by a error-message for human and a error-code for machine
- Recording the whole related error chain, if necessary
- Sending a proper HTTP response according to the error
To satisfy the requirement of Node.js environment, I have decided to introduce the LMError class to simplify and standardise the error-handling process in Node.js or other server-side JavaScript environments.
LMError class is extended from the standard Error class. By integrating with the support of error message & error code, HTTP response, and error chain, now all errors can be processed by one error-handler under a unified procedure.
npm install @leismore/lmos-nodejs-lmerror
npm test
npm run build
import { LMError, LMErrorErr, LMErrorRes } from '@leismore/lmos-nodejs-lmerror';
let error:LMErrorErr = { message: 'an error message', code: 'error_code_1984' };
let response:LMErrorRes = {
statusCode: '500',
headers: {
'Content-Type': 'text/html; charset=utf-8',
'Content-Language': 'en-GB'
},
body: `<!DOCTYPE html>
<html lang="en-GB">
<head>
<meta charset="UTF-8">
<title>500 Internal Server Error</title>
</head>
<body>
<h1>500 Internal Server Error</h1>
<p>Don't cry over spilt milk</p>
</body>
</html>`
};
let previous = new Error('standard Error');
throw new LMError(error, response, previous);type LMErrorErr = {
readonly message: string, // Message for human
readonly code: string // Code for machine
};
type LMErrorRes = { // HTTP response
readonly statusCode: string, // HTTP response status code
headers?: {readonly [key:string]: string}, // HTTP headers
body?: any // HTTP body
};public readonly error: LMErrorErr;
public readonly response?: LMErrorRes;
public previous?: Error;
public timestamp: Date;/**
*
* @throws Error
* invalid_error_message
* invalid_error_code
* invalid_http_statusCode
* invalid_http_header
* invalid_http_body
* invalid_previous
*
*/
public constructor(error: LMErrorErr, response?: LMErrorRes, previous?: Error)
/**
*
* @throws Error
* invalid_previous
* previous_exists
*
*/
public addPrevious(previous: Error):void
public toString(): string
© Leismore 2024
GNU AFFERO GENERAL PUBLIC LICENSE v3
- Kyle Chine since 02 Jul 2019
- Inspired greatly by http-errors
- Obsoleted package: @leismore/lmerror
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