Why is ', ' translated to '%2C+'?

Question

I am working on a project using Node.js v21.7.1, from a MariaDB database I query first name and surname then pass these back to the client.

In my SQL I use:

CONCAT(`t2`.`vcSurName`, ',', `t2`.`vcFirstName`) AS vcName

My client receives this and adds it to a 'SELECT' HTML tag, I can see the name is displayed correctly, for example 'Platten, Simon' is shown, this is now part of a form which when submitted, I can see that the server receives the name as:

'Platten%2C+Simon'

On the server I have used:

var strUserName = decodeURIComponent(objFields['biUID']);

I then split the name into an array:

var aryName = strUserName.split(', ');

This is where is goes wrong, decodeURIComponent only translates the %2C back to a comma, but the content of aryName now contains:

[Platten,+Simon]

What do I need to do because the + is the result of encoding the space but it doesn't get decoded...

Answer 1

decodeURIComponent() only handles the percentage-encoded parts of the string. Decoding the + character needs to be done separately.

See also the Decoding query parameters from a URL chapter of MDN's decodeURIComponent() article, where it suggests the following code:

function decodeQueryParam(p) {
  return decodeURIComponent(p.replace(/\+/g, " "));
}

decodeQueryParam("search+query%20%28correct%29");
// 'search query (correct)'