Normalize value-specific HttpHeaders deletions before filtering. The string overload previously used String#indexOf and removed shorter values contained within the requested deletion value, potentially widening outgoing request metadata.
Preserve delete-all behavior only when no value is supplied, and cover string, array, and empty-string deletion.
Prevent lazy HttpHeaders and HttpParams clones from reusing value arrays owned by a materialized source. Append and value-specific delete operations previously mutated those shared arrays, violating the immutable API contract and allowing request metadata to bleed into later requests.
Share value arrays until an update mutates a specific header or parameter, then copy only that array. Cover the affected append and delete paths with regression tests that materialize the source first.
when initialized from a `Headers` object containing multiple values for the same header, `HttpHeaders` now contains all the header values instead of only having one of them.
Fixes#57798
PR Close#57802
A lot of our tests are wrapped in `{}` which serves no purpose, aside from increasing the nesting level and, in some cases, causing confusion. The braces appear to be a leftover from a time when all tests were wrapped in a `function main() {}`. The function declaration was removed in #21053, but the braces remained, presumably because it was easier to search&replace for `function main()`, but not to remove the braces at the same time.
PR Close#52239
Some libraries could use numbers in headers. this fix prevents Angular from
throwing an error by casting those numerical values into strings.
Fixes#49353
PR Close#49379
HttpClient is an evolution of the existing Angular HTTP API, which exists
alongside of it in a separate package, @angular/common/http. This structure
ensures that existing codebases can slowly migrate to the new API.
The new API improves significantly on the ergonomics and features of the legacy
API. A partial list of new features includes:
* Typed, synchronous response body access, including support for JSON body types
* JSON is an assumed default and no longer needs to be explicitly parsed
* Interceptors allow middleware logic to be inserted into the pipeline
* Immutable request/response objects
* Progress events for both request upload and response download
* Post-request verification & flush based testing framework
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