microsoft / microsoft/TypeScript

--noImplicitAny codefix inferring string for complex object

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Domain: LS: Quick Fixes Experience Enhancement Suggestion
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Description

TypeScript Version: 3.3.0-dev.20190108

Search Terms: noimplicitany infer code fix codefix string object data

Code

function cleanup(data) {
  if (Array.isArray(data)) {
    return data.map(cleanup)
  }
  if (!data || typeof data !== 'object') return data

  let keys = Object.keys(data)
  if (keys.length <= 3 &&
    data.name &&
    (keys.length === 1 ||
      keys.length === 3 && data.email && data.url ||
      keys.length === 2 && (data.email || data.url))) {
    data = unparsePerson(data)
  }
  return data
}

Expected behavior:

--noImplicitAny suggested fix on the data parameter: unclear what this should be. Perhaps a fancy type union containing an anonymous object type with fields such as name and url?

Actual behavior:

function cleanup(data: string) {

Related Issues: #13243 (parent tracking quick fixes)

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 with the noImplicitAny codefix that annotates the cleanup parameter and reproduce the behavior using the TypeScript snippet in this issue. Read related issue #13243 for the parent quick-fix context; done means the codefix no longer infers string for this complex object case and its resulting behavior matches the agreed expected type.

Written by the indexing model from the issue text.

Assessment

Tech stack
typescript
Domain
compilers
Issue type
Bug
Difficulty
4/5
Estimated time
3-5 days
Activity status
Stale
Clarity
Needs clarification
Newbie friendliness
35/100

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