TypeScript: Missing Union Elements of Indexed Access Type

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Assessment

Difficulty
3/5
Estimated time
1-2 days
Newbie friendliness
45/100
Issue type
Bug
Clarity
Mostly clear
Activity status
Stale
Tech stack
react, typescript
Domain
documentation, tooling

Research direction

Start with the TypeScript example in the issue and reproduce it in the react-docgen playground. Trace how the indexed-access type is handled, then add coverage for the expected union literal elements and confirm the generated JSON includes the three literals shown.

Written by the indexing model from the issue text.

Description

typescript

Hello there,
In the following code, the elements of the size props are not outputted.

type Base = {
  size: "small" | "medium" | "large";  
};

type Props = {
  size: Base["size"];
}

const MyComponent = ({size}: Props) => {
  return <div />;
}

Result

[
  {
    "description": "",
    "displayName": "MyComponent",
    "methods": [],
    "props": {
      "size": {
        "required": true,
        "tsType": {
          "name": "union",
          "raw": "Base[\"size\"]"
        },
        "description": ""
      }
    }
  }
]

Expected Behavior

[
  {
    "description": "",
    "displayName": "MyComponent",
    "methods": [],
    "props": {
      "size": {
        "required": true,
        "tsType": {
          "name": "union",
          "raw": "\"small\" | \"medium\" | \"large\"",
          "elements": [
            {
              "name": "literal",
              "value": "\"small\""
            },
            {
              "name": "literal",
              "value": "\"medium\""
            },
            {
              "name": "literal",
              "value": "\"large\""
            }
          ]
        },
        "description": ""
      }
    }
  }
]

I reproduced it here:
https://react-docgen.dev/playground

Thanks for regards.

Dominant language
TypeScript
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