POST call expected response body type also set to request body type

[peetjvv]

Describe the bug

When specifying an expected response.data type to the post method it also sets that expected type to the request body. Also, when not specifying a type, the type for the response.data gets inferred to be the same as the type of the request body. This leads to typescript errors in VS Code and during compile time when the response and request bodies in code doesn't have the same type (which is usually the case). This was not an issue in v0.21.4 - which I reverted to in order to get around this issue.

To Reproduce

1. Install axios v0.22.0
2. Add a type for the response.data like in this example:

axios.post<ExpectedResponseBody>(`post url`, { foo: "bar" }, {});

Also look at the CodeSandbox example here

Expected behavior

When specifying the expected type of the response.data in the post call, the request body shouldn't have the same expected type. And the inferred type for the request body shouldn't automatically get applied to response.data.

Environment

• Axios Version 0.22.0
• Adapter N/A
• Browser N/A
• Browser Version N/A
• Node.js Version: 14.17.3
• OS: Win 10
• Additional Library Versions: Typescript 4.4.3

Additional context/Screenshots

Type for post method in axios v0.21.4

Type for post method in axios v0.22.0. Note that T is also set to request data and config in this version - which is what I believe is the cause of the issue.

[alessandrojcm]

Same problem here when updating to 0.22; it literally broke the whole app.

[TheVaan]

Duplicate to #4109

[peetjvv]

Duplicate to #4109

Thank you. I couldn't find an existing issue for this when I started writing up my issue on Saturday.

[TheVaan]

You're welcome. Axios team messed up with the last release. Maybe they deserve issue overflow 😶

[tjhorner]

Axios team messed up with the last release. Maybe they deserve issue overflow 😶

Yeah it's frankly concerning how this got through. We all make mistakes but this is a big one to miss 🙃

It looks like their TypeScript tests may be incorrectly written? I'm not sure, and I don't really want to dig into it... but I'm not sure why the tests didn't catch this.

axios/test/typescript/axios.ts

Lines 200 to 202 in 76f09af

	axios.post<Partial<UserCreationDef>, string>('/user', { name: 'foo' }, { headers: { 'X-FOO': 'bar' } })
	.then(handleStringResponse)
	.catch(handleError);

If I'm not mistaken, string should actually be AxiosResponse<string> here.

[peetjvv]

Axios team messed up with the last release. Maybe they deserve issue overflow 😶

Yeah it's frankly concerning how this got through. We all make mistakes but this is a big one to miss 🙃

It looks like their TypeScript tests may be incorrectly written? I'm not sure, and I don't really want to dig into it... but I'm not sure why the tests didn't catch this.

axios/test/typescript/axios.ts

Lines 200 to 202 in 76f09af

	axios.post<Partial<UserCreationDef>, string>('/user', { name: 'foo' }, { headers: { 'X-FOO': 'bar' } })
	.then(handleStringResponse)
	.catch(handleError);

If I'm not mistaken, string should actually be AxiosResponse<string> here.

Your assumption on the type is incorrect. it should be axios.post<string> which then returns a response of type AxiosResponse<string>. But good point on the tests - definitely should've picked this up.