Check if Param is empty or not in express.js

Question

I want to create a table and put on it all the param which are not empty in param like this

http://localhost:5002/[email protected]&[email protected]&m3=&m4=&m5=&m6=&m7=&m8=&[email protected]&m10=&[email protected]&m12=&m13=&m14=&m15=&m16=&m17=&m18=&m19=&v=4.1.2&hw=6

And after this i want to store all the email ( m1,m2,m9,m11 ) in a table.

console.log(b) // [email protected] , [email protected] , [email protected] , [email protected]

So I did it like this

    let emailTable = [req.query.m0,req.query.m1,req.query.m2......]
Box.push({Email:emailTable}}
console.log(Box)// it show me even the empty param, i want only the full one

I would encourage you to look at this question: https://stackoverflow.com/questions/9064127/how-to-parse-a-string-into-a-hashtable — idream1nC0de, Mar 14 '18 at 16:19
Given the details now in the question, I agree, they're not the same. — idream1nC0de, Mar 14 '18 at 16:24
The contents of `emailTable` are strings, I assume. Why not just use `Array.prototype.filter` to remove the empty values? — idream1nC0de, Mar 14 '18 at 16:25
@JacobHeater Should i do something like this let filtredTable=emailTable.filter(); console.log(filtredTable); — Taieb, Mar 14 '18 at 16:34
You can use `emailTable.filter(p => !!p)` to filter out the empty strings in the array. — idream1nC0de, Mar 14 '18 at 18:26

score 0 · Answer 1 · answered Mar 14 '18 at 16:33

Here is simple solution to the problem JSFIDLE: https://jsfiddle.net/85bzj3a3/7/

// Lets imagine this object is your req.param
reqParam = {
  m1: 'email1',
  m2: '',
  m3: 'email3',
  m4: 'email4',
  someOther1: 'some other param',
  m5: '',
  m61: 'email6',
  someOther: 'otherValue'
}

const  emailTable = []
for (let key of Object.keys(reqParam)){
    // check if it is email and if it has value
  if(key.match(/^[m]+[0-9]*$/g) != null && reqParam[key] != ''){
    emailTable.push(reqParam[key])
  } 
}
console.log(emailTable)

What I did, is go through paramerers, check if it is email parameter using regex, and then check if it has value, if it does, push it to emailTable.

I dont think it is smart to hard code all parameters when pushing to array, since next time you add another parameter in url, you have to hardcode it again in your function, which is no bueno.

score 0 · Answer 2 · answered Mar 14 '18 at 19:00

Here's my solution to your problem. I am using lodash to make things a bit easier to read. The native implementation to this problem should be pretty easy to figure out. My index.js file contains VERY simple Express server that can print query string parameters to the console. Let me know if you still have questions.

// Request URL: http://localhost/?&m1=Has%20value&m2=&m3=&[email protected]

const express = require('express');
const app = express();
const _ = require('lodash');

app.get('/', (req, res) => {

    const params = _.values(req.query);

    console.log(params); // [ 'Has value', '', '', '[email protected]' ]

    const withValues = _.filter(params, p => !!p);

    console.log(withValues); // [ 'Has value', '[email protected]' ]

    res.sendStatus(200);

});

app.listen(80);

Check if Param is empty or not in express.js

2 Answers2