Normalize user-provided HttpLink headers by lower-casing their names. #8449
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lgtm |
| ): typeof headers { | ||
| if (headers) { | ||
| const normalized = Object.create(null); | ||
| Object.keys(Object(headers)).forEach(name => { |
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I wonder why you chose the forEach approach instead of return reduce. In this day and age, everyone is liking their immutability very much, even in such trivial cases. Is it just preference?
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I sometimes do use reduce, but reduce would still require mutating the normalized object to accumulate the properties if you don't want to shallow-clone the object every time you add a single property (which wastes memory and time). From that perspective, a forEach loop is faster and simpler to read than a (naive copying) reduce loop. No need to guess which callback parameter is which!
On a more general note, I like immutability, but I like it best when it doesn't require me to allocate and throw away a ton of immutable objects along the way to the final object, when simple mutation of would work and be safe, because no one else has seen this object reference yet.
Should fix #8447, by preferring the last (according to
Object.keys(headers)) header among multiple headers whose names are case-insensitively equivalent.I'm a little worried this could be a user-visible change in some (HTTP-specification-violating) situations. If so, we can easily retarget this PR to the
release-3.4branch, and make a clear note of it inCHANGELOG.md.