Proper way to parse Boolean query string param in node/express

Question

I'm waiting for something like the following from the front end

....?isUpdated=true

so I did something like this in code (as I'm processing only isUpdated=true, false need to be ignored)

var isUpdated = (req.query.isUpdated === 'true')

but it seems bit odd to me.

How to do this in proper way? I mean to parse a Boolean parameter from the query string.

Answer 1

Docs if you are using query-string

const queryString = require('query-string');

queryString.parse('foo=true', {parseBooleans: true});
//=> {foo: true}

Answer 2

The only thing I would change about your approach is to make it case insensitive:

var isUpdated = ((req.query.isUpdated+'').toLowerCase() === 'true')

You could make this a utility function as well if you like:

function queryParamToBool(value) {
  return ((value+'').toLowerCase() === 'true')
}
var isUpdated = queryParamToBool(req.query.isUpdated)

Answer 3

I use this pair of lines:

let test = (value).toString().trim().toLowerCase(); let result = !((test === 'false') || (test === '0') || (test === ''));

Answer 4

Here is my generic solution for getting a query params as a boolean:

const isTrue = Boolean((req.query.myParam || "").replace(/\s*(false|null|undefined|0)\s*/i, ""))

It converts the query param into a string which is then cleaned by suppressing any falsy string. Any resulting non-empty string will be true.