HttpParams : Handling of null & undefined values

I’m submitting a…

[ ] Regression
[x] Bug report
[ ] Feature request
[ ] Documentation issue or request
[ ] Support request

Current behavior

new HttpParams().set('arg', null).toString(); // "arg=null"
let a = {};
new HttpParams().set('arg', a.any).toString(); // "arg=undefined"

Expected behavior

new HttpParams().set('arg', null).toString(); // "arg="
let a = {};
new HttpParams().set('arg', a.any).toString(); // "arg="

Minimal reproduction of the problem with instructions

https://github.com/angular/angular/blob/master/packages/common/http/src/params.ts#L57 This is due to the underlying encodeURIComponent return string literals for “null” or “undefined”;

(edited) Plnkr replication : https://embed.plnkr.co/k5naIib3sGADM91UZ31a/

What is the motivation / use case for changing the behavior?

This has mostly arisen due to HttpClient, and replacement of URLSearchParams, with HttpParams

Is this an intended behaviour, or does this require a fix? e.g.

• null and undefined are converted to ""? or;
• null is "", and undefined is thrown?

I appreciate these are not intended as direct replacements, and you can create your own HttpParameterCodec, but this seems like an unintended operation.

Environment

Angular version: 4.3.3

Browser:
- [x] Chrome (desktop) version 60.0