URLSearchParams.set() not behaving like specified

[chrisdirnberger]

Hey there, I found a small little something on the URLSearchParams interface:

The URLSearchParams.set() method does not create the parameter if it does not yet exist. Version: v0.1.14-beta

As documented here https://url.spec.whatwg.org/#dom-urlsearchparams-set and here https://developer.mozilla.org/en-US/docs/Web/API/URLSearchParams/set the set() method should behave like this:

The set() method of the URLSearchParams interface sets the value associated with a given search parameter to the given value. If there were several matching values, this method deletes the others. If the search parameter doesn't exist, this method creates it.

In the browser both variants will return the same result, whilst running on the llrt the behavior differs.

const searchParams = new URLSearchParams('?foo=&bar=baz');
searchParams.set('foo', 'bar');
console.log(searchParams.toString()); // returns foo=bar&bar=baz

const searchParams = new URLSearchParams('?bar=baz');
searchParams.set('foo', 'bar');
console.log(searchParams.toString()); // returns bar=baz

Workaround in the meantime:

if(searchParams.has('foo')) {
  searchParams.set('foo', 'bar');
} else {
  searchParams.append('foo', 'bar');
}

[richarddavison]

Thanks for spotting!

[richarddavison]

Fixed in https://github.com/awslabs/llrt/pull/397