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Duc Ng
Duc Ng

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How to create your command-line program (CLI) with NodeJS and Commander.js

#javascript #node

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This post will show you how to create a command-line npm module (CLI) using Commander.js module.

Commander.js is a very popular module that lets you create your own CLI program.

First, start your new project - let's say my project name is "json-now"

$ git clone https://github.com/yourname/json-now.git $ cd json-now
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Now, create your package.json file:

{ "name": "json-now", "version": "0.0.1", "bin": { "json-now": "./bin/index.js" }, "dependencies": { "commander": "^3.0.1" } }
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Then, install dependencies:

$ npm install
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The "bin" section specifies your command line name. As you see, go ahead and create a "bin" directory with "index.js" file there:

#!/usr/bin/env node const program = require('commander'); const ver = require('../lib/ver'); program .usage('[options] <file>') .option('-v, --version', 'show version', ver, '') .option('-p, --port <port>', 'use custom port') .option('-f, --flag', 'boolean flag', false) .action((file, options) => { console.log('file name: ', file); // more hanlder: require('../lib/moreHandler')(options); }) .parse(process.argv);
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Let's create the very first option called "-v" or " - version" which shows version number. Create a directory named "lib" and a new file "ver.js" there:

const package = require('../package.json') module.exports = () => { console.log(package.version); };
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So far, it looks straight forward. You created a commander "program" which handles option like "-v" by running "ver.js"

Open Terminal and try it out:

$ node bin/index.js -v 0.0.1 $ node bin/index.js sample.json file name: sample.json
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Now, it's time to publish your command line for the world to use!

$ npm login $ npm publish Try out your shiny new command: $ npm install json-now -g $ json-now -v
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The above code is located here for your reference:

https://github.com/ngduc/api-now

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