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This commit adds the append method for the Headers API. @malisas and I are both contributors.
There are a few TODOs related:
- The script needs to parse the header value for certain header names to decide the header group it belongs
- There are possible spec bugs that could change what a valid header value looks like (related: [issue page](https://github.com/whatwg/fetch/issues/332))
There are WPT tests already written for the Headers API, but they will fail as the Headers API is not fully implemented.
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<!-- Thank you for contributing to Servo! Please replace each `[ ]` by `[X]` when the step is complete, and replace `__` with appropriate data: -->
- [X] `./mach build -d` does not report any errors
- [X] `./mach test-tidy` does not report any errors
- [ ] These changes fix #__ (github issue number if applicable).
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- [ ] There are tests for these changes OR
- [X] These changes do not require tests because tests for the Headers API already exists, but this commit does not implement the interface fully. The tests will fail.
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Source-Repo: https://github.com/servo/servo
Source-Revision: 03fa7f0ba533acc44100639ad85625810618df3a
