Incorrect TypeScript definition for Menu Component defaultProps

Version

3.1.0

Environment

Chrome

Reproduction link

https://codesandbox.io/s/o7lxqxy7xz

Steps to reproduce

Version: 3.1.0

Menu Component’s defaultProps is defined as:

static defaultProps: {
    theme: string;
    ...
};

But MenuProps interface is expecting:

theme?: 'light' | 'dark';

What is expected?

No error

What is actually happening?

This is causing TypeScript compiler to throw:

Error:(87, 25) TS2345: Argument of type 'typeof Menu' is not assignable to parameter of type 'string | ComponentClass<MenuProps> | StatelessComponent<MenuProps>'.
  Type 'typeof Menu' is not assignable to type 'StatelessComponent<MenuProps>'.
    Types of property 'defaultProps' are incompatible.
      Type '{ prefixCls: string; className: string; theme: string; }' is not assignable to type 'Partial<MenuProps>'.
        Types of property 'theme' are incompatible.
          Type 'string' is not assignable to type '"light" | "dark"'.

---

This can be corrected by changing defaultProps to:

static defaultProps: {
    theme: 'light' | 'dark';
    ...
};

[jmca]

@dengfuping I’m thinking it’s an issue with TS Inference. Here’s a quick page on it: https://basarat.gitbooks.io/typescript/docs/types/literal-types.html

Referring to https://github.com/ant-design/ant-design/blob/c14b13d4acbf0c51f0ef67a93270516ac0572a0a/components/modal/Modal.tsx#L98 TS is inferring that this prop should be a string type.

The solution could possibly be to just cast the prop:

static defaultProps = {
    ...
    okType: 'primary' as ButtonType,
};

Then the extracted .d.ts files should infer the correct type (ButtonType instead of string).

[eddiemoore]

Will see if I can find some time to submit a PR