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Bug: [prefer-optional-chain] should report case that can be converted to optional function call ?.() #11270

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kirkwaiblinger opened this issue Jun 4, 2025 · 1 comment · May be fixed by #11272
Open
4 tasks done

Bug: [prefer-optional-chain] should report case that can be converted to optional function call ?.() #11270

kirkwaiblinger opened this issue Jun 4, 2025 · 1 comment · May be fixed by #11272
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accepting prs Go ahead, send a pull request that resolves this issue bug Something isn't working package: eslint-plugin Issues related to @typescript-eslint/eslint-plugin

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@kirkwaiblinger
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kirkwaiblinger commented Jun 4, 2025 •
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Before You File a Bug Report Please Confirm You Have Done The Following...

  • I have tried restarting my IDE and the issue persists.
  • I have updated to the latest version of the packages.
  • I have searched for related issues and found none that matched my issue.
  • I have read the FAQ and my problem is not listed.

Playground Link

https://typescript-eslint.io/play/#ts=5.6.3&fileType=.tsx&code=CYUwxgNghgTiAEYD2A7AzgF3gMyUgXPAN4BQ88AtiBgBZLCECuKo2AliiMPAD7wAU-AJTwAvAD54ANyRtgQkgF8SJXEgB0VWvXgAyXTjybqdYMIDcQA&eslintrc=N4AhCgwIgJwVwDYFMDOUBcJiTCKABAFwE8AHVAYxgEtTCBaVBagO0IHpSYkAzJGegHs61QSwCGCehQAW41hjwB3cTBZQcAX3CagA&tsconfig=N4KABGBEDGD2C2AHAlgGwKYCcDyiAuysAdgM6QBcYoEEkJemy0eFYDAruuGAL4g9A&tokens=false

Repro Code

declare const foo: {
  method: undefined | (() => void)
}

foo.method && foo.method();

ESLint Config

module.exports = {  
  "rules": {
    "@typescript-eslint/prefer-optional-chain": "warn"
  }
}

tsconfig

{
  "compilerOptions": {
    "strict": true
  }
}

Expected Result

I expect that the rule should report and suggest foo.method?.().

Actual Result

No report

Additional Info

This is specifically implied in the docs examples with the line foo && foo.a && foo.a.b && foo.a.b.method && foo.a.b.method();

Relates to #9605
@kirkwaiblinger kirkwaiblinger added bug Something isn't working package: eslint-plugin Issues related to @typescript-eslint/eslint-plugin triage Waiting for team members to take a look labels Jun 4, 2025
@kirkwaiblinger
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Oh, this appears to be a case specifically around the return type being void...

(playground)

declare const foo: {
  returnsVoid: undefined | (() => void)
  returnsString: undefined | (() => string)
}

// does not report
foo.returnsVoid && foo.returnsVoid();
// reports
foo.returnsString && foo.returnsString();

At least in cases where the return value is not used, I'd think we should report these kinds of expressions. This is a prime use case for ?.(), since patterns like context.optionalCallback?.(); arise naturally.

@bradzacher bradzacher added accepting prs Go ahead, send a pull request that resolves this issue and removed triage Waiting for team members to take a look labels Jun 5, 2025
@nayounsang nayounsang linked a pull request Jun 5, 2025 that will close this issue
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