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JavaScript Node.js Basics 2017 Building a Command Line Application Capturing Command Line Arguments

Why in the video when we use const users = process.argv.slice(2) we don't need the line const username = ['chalkers',~~]

The note I am taking from the video

//make the application flexible

//wrap the code in a function get Profile function getProfile(username) { // Connect to the API URL (https://teamtreehouse.com/username.json) const request = https.get(https://teamtreehouse.com/${username}.json, response => { let body = ""; // Read the data response.on('data', data => { body += data.toString(); });

response.on('end', () => { // Parse the data const profile = JSON.parse(body);
// Print the data printMessage(username, profile.badges.length, profile.points.JavaScript); }); }); }

// const username = ['chalkers','alenaholligan', 'dave']; // getProfile('chalkers'); // getProfile('alenaholligan');

                    //slice here from the 3rd number in an array, we don't want the first 2

const users = process.argv.slice(2); //command line like node app.js chalker alena dave to check data users.forEach(getProfile); //shorten //users.forEach(usernmae => { getProfile(usernmae); }

Henry Blandon
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Henry Blandon
Full Stack JavaScript Techdegree Graduate 21,485 Points

Hanwen Zhang, The process.argv property returns an array containing the command-line arguments passed when the Node.js process was launched. This mean you pass the user name information in the command-line, like so: node app.js chalkers alenaholligan dave. in addition of the names you pass, it will return two more element in the array index 0 and index 1, you do no want the first two, therefore you slide them. if you try console.log(process.argv) you should be able to see the first two elements I am talking about.

1 Answer

Hi Hanwen,

I’m not 100% sure that I understand your question, but if you’re wondering why you use the slice method, it’s because argv will return the following array:

[‘node’, ‘app.js’, ‘chalker’, ‘alena’, ‘dave’].

It returns every string that makes up the command, but you only want to pass the final three into the for loop.

Does that answer your question?