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.

Solution 1

Docs if you are using query-string

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

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

Solution 2

I use this pair of lines:

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

Solution 3

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)

Solution 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.

Solution 5

You can use qs package

A little code to parse int and booleans

qs.parse(request.querystring, {
      decoder(str, decoder, charset) {
            const strWithoutPlus = str.replace(/\+/g, ' ');
            if (charset === 'iso-8859-1') {
              // unescape never throws, no try...catch needed:
              return strWithoutPlus.replace(/%[0-9a-f]{2}/gi, unescape);
            }

            if (/^(\d+|\d*\.\d+)$/.test(str)) {
              return parseFloat(str)
            }

            const keywords = {
              true: true,
              false: false,
              null: null,
              undefined,
            }
            if (str in keywords) {
              return keywords[str]
            }

            // utf-8
            try {
              return decodeURIComponent(strWithoutPlus);
            } catch (e) {
              return strWithoutPlus;
            }
          }
})

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