How to compile or check syntax error in Node.js application

Question

I have created a node.js application. I need to compile or do a check whether syntax error occurs before running the node.js service.I need to integrate this in jenkins. Kindly guide me to validate the node.js application

Answer 1

Look into TypeScript. It is a language which allows you to get autocomplete with types and fails compilation if you have some syntax errors. It is a superset of JavaScript and transpiles to JavaScript.

Answer 2

Node.js provides CLI option --check or -c for checking a given file for syntax errors without running it. When working with Linux or MacOS a command like the following one helps with checking all obvious javascript files in a folder for containing basically working code:

find -name "*.js" | xargs node -c

Answer 3

You can use 'node-syntax-error' module. it helps you to detect and report syntax errors in source code strings.

When you type node src.js you get a friendly error report about exactly where the syntax error is. This module lets you check for syntax errors and report them in a similarly friendly format that wrapping a try/catch around Function() or vm.runInNewContext() doesn't get you.

For example:

var fs = require('fs');
var check = require('syntax-error');

var file = __dirname + '/src.js';
var src = fs.readFileSync(file);

var err = check(src, file);
if (err) {
    console.error('ERROR DETECTED' + Array(62).join('!'));
    console.error(err);
    console.error(Array(76).join('-'));
}

Answer 4

Use the following code for checking syntax error in node.js application -

var check = require('syntax-error')

Check the source code string src for syntax errors. Optionally you can specify a filename file that will show up in the output. If src has a syntax error, return an error object err that can be printed or stringified. If there are no syntax errors in src, return undefined.

var err = check(src, file)

Answer 5

Using

node --check

Only finds very grave errors and can be tricky to execute.

I would suggest to use a linter like 'eslint'. Because:

• It integrates easily with (npm lint or yarn lint)
• It catches almost all possible errors (way more than node -check)

Answer 6

using eslint package https://www.npmjs.com/package/eslint It's a very common library to check the syntax of any JS/TS framework