* Fixed isFormData predicate;
Added support for automatic object serialization to FormData if `Content-Type` is `multipart/form-data`;
Added support for FormData to be overloaded using `config.env.FormData` option;
Added support for FormData in node.js environment through `form-data` package;

* Added the `form-data` package as a dependency for the server build;
Added tests for FormData payload;

* Added FormData automatic serialization section;
Refactored cancellation section;

* Reworked toFormData helper;
Expose toFormData helper as a static method;
Refactored transform request;
Added kindOf, kindOfTest, endsWith, isTypedArray util;
Refactored utils.js to use kindOf for tests;

* Fixed isFormData predicate; (#4413)

Added support for automatic object serialization to FormData if `Content-Type` is `multipart/form-data`;
Added support for FormData to be overloaded using `config.env.FormData` option;
Added support for FormData in node.js environment using `form-data` package;

(cherry picked from commit 73e3bdb8)

* Added shortcut methods `postForm`, `putForm`, `patchForm` to submit a Form;
Added ability to submit FileList object as a FormData;
Updated README.md;

* Updated README.md;

Adding baseURL to be used in getUri(), also removing question mark trimming since there seems to be no obvious reason for it. (#3737)
Co-authored-by: NJay <jasonsaayman@gmail.com>

* Fixing error returned when requesting illegal URL

* Adding unit tests http.js

* Fixing error message axios invalid request from browser

* Adding unit tests requests.spec.js

* Adding at utils.js a new method: getProtocol
Co-authored-by: NJay <jasonsaayman@gmail.com>

Co-authored-by: NJay <jasonsaayman@gmail.com>

This reverts commit 73e3bdb8.

Added support for automatic object serialization to FormData if `Content-Type` is `multipart/form-data`;
Added support for FormData to be overloaded using `config.env.FormData` option;
Added support for FormData in node.js environment through `form-data` package;

* Removed error when url is null as this breaks current use cases for alot of projects

* Removed associated tests that check for the for url to not be empty

* Fixing error message when missing url

* Fixing missing url

* Adding missing url case

* Update Axios.js

* Update requests.spec.js

* Update api.spec.js

* Update api.spec.js

* Update api.spec.js
Co-authored-by: NJay <jasonsaayman@gmail.com>

* adding toFormData test

* adding toFormData
Co-authored-by: NJay <jasonsaayman@gmail.com>

* Add a group for the multiple-interceptors tests.

The current test contains a lot of details that are worth being tested
separately and also made explicit. This is what is coming with the next changes.

* Fix indentation.

* Make explicit that the test only tests the interception of the fulfilled part.

* Indent.

* Make the test just test a tiny bit, as described.

The more explicit the test, the better we can 1) describe what it does
and use that for the docs to make them understandable 2) have a better
explicit description of the API (in case we want to modify it) and 3) have
a regression test when changing.

* Add a test that explicitly shows that the order of interceptors is as they were added.

* Pull out reusable code, to make the tests more explicitly stating the things they care about.

* Write a test showing that the responses are not merged or anything,
only the last one in the chain is returned.

* Make visible that the interceptors are a chain, one receives its predecessor's data.

* Test what happens when the interceptor throws.

* Refactor, add another group of tests and pull helper function there.

The previous change to also catch in the helper function was not needed
for any of the tests above, so remove it and put it in the describe-block
below where it is needed.
Just trying to write the specific code needed, not more.
Not sure about the impact for failing tests, I am glad about input.
But the main intention here is to have minimal code, explicit tests and
not too much generic code which might break itself eventually.

* Documenting that the following reject-interceptor gets called.

* Documenting how the interceptor chain handles caught rejections.

* Document "multiple interceptors".

I just extracted the test descriptions from the new/modified tests.
And I also learned that I should improve the test descriptions, the
tests are just in a GIVEN-WHEN-THEN structure, so I can also use those
terms better. Will do this next.

* Transfer the better readable descriptions as I changed them in the README back into the tests.

After I had updated the README using the test descriptions I realized how
the test descriptions can be improved, so I did this "moving" the learnings
back into the code.

* Be a bit more explicit, it was not clear when reading, imho.

* Add new lines to be kinda consistent with the rest of the file.
Co-authored-by: NJay <jasonsaayman@gmail.com>

1. add the judgment of null
Co-authored-by: NJay <jasonsaayman@gmail.com>

Refactored `Cancel` to a constructor, a subclass of the `AxiosError`;
Expose CanceledError class;
Refactored axios error codes;
Added `toFlatObject` util;

* fix/Avoid package.json import; (#4041)

* Added auto-generated config module `env/data.js` for importing package environment vars without importing the whole `package.json`;
Refactored `http.js` to use `env/data.js` instead of package.json;

* Added `env/data.js`;
Added `env/README.md`;

* Feat/export package version constant (#4065)

* Added auto-generated config module `env/data.js` for importing package environment vars without importing the whole `package.json`;
Refactored `http.js` to use `env/data.js` instead of package.json;

* Added `env/data.js`;
Added `env/README.md`;

* Export package version constant;

* Fixed cancelToken leakage; Added AbortController support; (#3305)

* Fixed cancelToken leakage;
Added AbortController support;

* Fixed typings;

* Documented `signal` option;

* Added processing of early cancellation using AbortController without sending a request;
Co-authored-by: NJay <jasonsaayman@gmail.com>

* Updating CI to run on release branches

* Fixed default transitional config for custom Axios instance; (#4052)

Refactored `/core/mergeConfig`;
Co-authored-by: NJay <jasonsaayman@gmail.com>

* Prepping v0.22.0 for release

* Updated date
Co-authored-by: NDmitriy Mozgovoy <robotshara@gmail.com>

* fix json transform when data is pre-stringified (#4020)

* [Updating] incorrect JSON syntax in README.md

* [Releasing] v0.21.4
Co-authored-by: NGuillaume FORTAINE <guillaume+github@fortaine.com>

* Adding HTTP status code to error.toJSON (axios#2947)

* Adding Error display div to internal server client.html
Co-authored-by: NJay <jasonsaayman@gmail.com>

* removed charset setting when setting default header

* Remove charset from tests
Co-authored-by: Nmpark86 <dev.minuk.park@gmail.com>
Co-authored-by: NJay <jasonsaayman@gmail.com>
Co-authored-by: NPilot <timemachine@ctrl-c.club>

* Draft

* Added support for primitive types to be converted to JSON if the request Content-Type is 'application/json';
Added throwing SyntaxError if JSON parsing failed and responseType is json;
Added transitional option object;
Added options validator to assert transitional options;
Added transitional option `silentJSONParsing= true` for backward compatibility;
Updated README.md;
Updated typings;

* Fixed isOlderVersion helper;
Fixed typo;
Added validator.spec.js;

* Added forcedJSONParsing transitional option #2791

* `transformData` is now called in the default configuration context if the function context is not specified (for tests compatibility);

* Added `transitional.clarifyTimeoutError` to throw ETIMEDOUT error instead of generic ECONNABORTED on request timeouts;
Added support of onloadend handler if available instead of onreadystatechange;
Added xhr timeout test;
Fixed potential bug of xhr adapter with proper handling timeouts&errors (FakeXMLHTTPRequest failed to handle timeouts);

* Removed unnecessary assertion;

JSON improvements: throw if JSON parsing failed; number, boolean can be passed directly as payload for encoding to JSON #2613, #61, #907 (#3688)

* Draft

* Added support for primitive types to be converted to JSON if the request Content-Type is 'application/json';
Added throwing SyntaxError if JSON parsing failed and responseType is json;
Added transitional option object;
Added options validator to assert transitional options;
Added transitional option `silentJSONParsing= true` for backward compatibility;
Updated README.md;
Updated typings;

* Fixed isOlderVersion helper;
Fixed typo;
Added validator.spec.js;

* Added forcedJSONParsing transitional option #2791

* `transformData` is now called in the default configuration context if the function context is not specified (for tests compatibility);

* Added `transitional.clarifyTimeoutError` to throw ETIMEDOUT error instead of generic ECONNABORTED on request timeouts;
Added support of onloadend handler if available instead of onreadystatechange;
Added xhr timeout test;
Fixed potential bug of xhr adapter with proper handling timeouts&errors (FakeXMLHTTPRequest failed to handle timeouts);

* issue#2609 | Sasha | predictable axios requests

- axios requests are not delayed by pre-emptive promise creation by default
- add options to interceptors api ("synchronous" and "runWhen")
- add documentation and unit tests

* issue#2609 | Sasha | pull request feedback changes

* issue#2609 | Sasha | additional feedback changes

* issue#2609 | Sasha | put back try/catch

* issue#2609 | Sasha | add 2 adapter unit tests

- remove check for requestCancelled
Co-authored-by: Nak71845 <alexandre.korotkov@kroger.com>
Co-authored-by: NXianming Zhong <chinesedfan@qq.com>
Co-authored-by: NJay <jasonsaayman@gmail.com>

Co-authored-by: NJason Kwok <JasonHK@users.noreply.github.com>

Fix typos

Co-authored-by: NJay <jasonsaayman@gmail.com>

* Adding failing test

* Fixing #2587 default custom config persisting

* Adding Concat keys and filter duplicates

* Fixed value from CPE

* update for review feedbacks

* no deepMerge

* only merge between plain objects

* fix rename

* always merge config by mergeConfig

* extract function mergeDeepProperties

* refactor mergeConfig with all keys, and add special logic for validateStatus

* add test for resetting headers

* add lots of tests and fix a bug

* should not inherit `data`

* use simple toString

* revert #1845
Co-authored-by: NDavid Tanner <david.tanner@lifeomic.com>
Co-authored-by: NJustin Beckwith <justin.beckwith@gmail.com>

Co-authored-by: NJay <jasonsaayman@gmail.com>

This reverts commit a9a3b5e2.

* Fixing default transformRequest of TypedArrays with buffer pools

A buffer pool is a large ArrayBuffer of a preset size used with a TypedArray
such as Uint8Array. This can speed up performance when constructing TypedArrays
of unknown sizes, and is a technique used by Node with their Buffers, and
by libraries like dcodeIO/protobuf.js.

Because the ArrayBuffer of such a TypedArray is much longer than the array
itself, using `.buffer` to transform the array before POSTing results in
sending a request with many extraneous empty bytes, which is wastefule and may
result in unexpected behavior.

Using `.slice()` before grabbing the ArrayBuffer fixes the problem by creating
a new TypedArray with a buffer of the expected length.
Signed-off-by: NZac Delventhal <delventhalz@gmail.com>

* Adding test for using default transformRequest with buffer pools

Adds a new test to the default transformRequest, running it on a
Uint8Array with a byte length of 16, but a much larger ArrayBuffer
with a byte length of 256. The transformed array should not include
any extra bytes, and so must have a byte length of just 16.
Signed-off-by: NZac Delventhal <delventhalz@gmail.com>
Co-authored-by: NZac Delventhal <zac@bitwise.io>
Co-authored-by: NJay <jasonsaayman@gmail.com>

* removing @ character from replacement list since it is a reserved character

* Updating buildURL test to not include the @ character

* Removing console logs
Co-authored-by: NJay <jasonsaayman@gmail.com>

* Fixing password encoding with special characters in basic authentication

* Adding test to check if password with non-Latin1 characters pass
Co-authored-by: Npetr.mares <petr.mares@linecorp.com>
Co-authored-by: NJay <jasonsaayman@gmail.com>

This reverts commit 920510b3.

* Failing test for #1252

* Only delete header keys that match an HTTP verb if the value is a non-string
Co-authored-by: NDavid Ko <david.ko@pvtmethod.com>
Co-authored-by: NJay <jasonsaayman@gmail.com>

* fix issue #2416, #2396

* fix Eslint warn

* Modify judgment conditions

* add unit test

* update unit test

* update unit test

* Name function to avoid ESLint func-names warning

* Switch params config to merge list and update tests

* Restore testing of both false and null

* Restore test cases for keys without defaults

* Include test for non-object values that aren't false-y.

* Remove unnecessary XSS check introduced by #2451

* Remove test file of `isValidXss`