microsoft / microsoft/TypeScript

Support typedef inheritance with JSDoc

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#20,077 10 comments 102 reactions 0 assignees View on GitHub

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Domain: JSDoc In Discussion Suggestion
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Description

TypeScript Version: 2.7.0-dev.20171116

Code

/**
 * @typedef {Object} Base
 * @property {String} baseProp
 */

/**
 * @typedef {Base} Child
 * @property {String} childProp
 */

/** @type {Child} */
const child = { baseProp: '' };

Expected behavior: Error. child is missing the childProp property.

Actual behavior: No error. The Child type is identical to the Base type and only requires a baseProp property. The childProp property definition is completely ignored.

Or maybe there's another way to do the equivalent of interface Child extends Base here?

Contributor guide

Open the contributing guide

First steps

  1. Read the whole issue, then the project's contributing guide.
  2. Comment on the issue to say you are picking it up — it saves two people doing the same work.
  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

Research direction

Start by reproducing the JSDoc typedef example from the issue and trace TypeScript's handling of typedef inheritance and @property declarations. Done means the checker reports that Child is missing childProp, or documents and implements the supported equivalent of interface Child extends Base.

Written by the indexing model from the issue text.

Assessment

Tech stack
javascript, typescript
Domain
compilers
Issue type
Bug
Difficulty
4/5
Estimated time
3-5 days
Activity status
Stale
Clarity
Clearly specified
Newbie friendliness
45/100

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