Got: Fix `got.mergeOptions` docs

[Gamaranto]

Describe the bug

• Node.js version:
• OS & version:

Actual behavior

The objects get merged like with a normal spread operation {...defaultOptions, ...newOptions}
...

Expected behavior

The result of got.mergeOptions should be {foo: 'x', bar: 'y'}
...

Code to reproduce

import got, { Options } from 'got';

const defaultOptions: Options = {
  responseType: 'json',
  json: {
    foo: 'x',
  },
};

const newOptions: Options = {
  json: {
    bar: 'y',
  },
};

console.log(got.mergeOptions(defaultOptions, newOptions).json);
// {bar: 'y'}
console.log(got.mergeOptions(newOptions, defaultOptions).json);
// {foo: 'x'}

Checklist

• [x] I have read the documentation.
• [x] I have tried my code with the latest version of Node.js and Got.

[szmarczak]

This is actually the correct behavior. It's like you would want to merge body: 'a' and body: 'b' and expect body: 'ab' - these are two different payloads.

[szmarczak]

The documentation needs to be fixed

[goto1]

It sounds like this statement in the documentation has some caveats:

got.mergeOptions(parentOptions, newOptions)

• If the new property is a plain object:
  
  
  
  • If the parent property is a plain object too, both values are merged recursively into a new object.
  
  

So for example form, json, and body wouldn't get "merged" but instead it would use values from properties coming from the newOptions object, is that correct?

[szmarczak]

yup

[goto1]

Got it. I could take a look and have a crack at it.

[szmarczak]

Fixed in 157e02bcb613ab506829326e7af96e8155b4e186