* 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: David Tanner <david.tanner@lifeomic.com>
Co-authored-by: Justin Beckwith <justin.beckwith@gmail.com>
Inside Axios.prototype.request function, It's forced to set
method to 'get' after `mergeConfig` if config.method exists, which makes the defaults.method not effective.