Add lint rule to prefer `map((): T => {})` over `map<T>(() => {})` #6995

jtbandes · 2023-10-14T02:14:10Z

User-Facing Changes
None

Description

TypeScript currently widens inferred types of function expressions (microsoft/TypeScript#241). This results in the following sad situation:

const a = [1, 2, 3];

type T = {
    x: number;
}

a.map((i): T => {
    return {
        x: i,
        y: "oopsie",  // error 👍
    }
});

a.map<T>((i) => {
    return {
        x: i,
        y: "oopsie",  // no error 🤔
    }
});

This PR adds a lint rule to automatically replace map<T>((i) => ... with map((i): T => ....

Depends on #6989 to merge first.

Resolves FG-5336

defunctzombie

magical - life is so hard in the salt mines

…ument

…oxglove#6995) **User-Facing Changes** None **Description** TypeScript currently widens inferred types of function expressions (microsoft/TypeScript#241). This results in the following [sad situation](https://www.typescriptlang.org/play?#code/MYewdgzgLgBAhjAvDA2gRgDQwExYMwC6A3AFAlQCeADgKYwAqSMA3iTOzAB4BcMYArgFsARjQBOpAL5k4AOkFwqACiUBLAJS9GiAHwsSAegMwAegH42HMTSj8xYfRyddeqjJecwKvAEQgQVBCqND5YMEYw4mIgYjCAvBuAsjseMNKS6qQkcgpUADz0OioaSHqsEebJ1rb2jp4uMG7JTt4wfgFBIWERYCCRYtGxgHwbgCi7yanpZEA): ```ts const a = [1, 2, 3]; type T = { x: number; } a.map((i): T => { return { x: i, y: "oopsie", // error 👍 } }); a.map<T>((i) => { return { x: i, y: "oopsie", // no error 🤔 } }); ``` This PR adds a lint rule to automatically replace `map<T>((i) => ...` with `map((i): T => ...`. Depends on foxglove#6989 to merge first. Resolves FG-5336

Add lint rule to prefer map((): T => {}) over map<T>(() => {})

826c2ee

jtbandes requested review from bryfox, defunctzombie, cfoust and snosenzo October 14, 2023 02:14

vercel bot had a problem deploying to Preview October 14, 2023 02:14 Failure

jtbandes mentioned this pull request Oct 14, 2023

Fix bug with subscription fields #6989

Merged

defunctzombie approved these changes Oct 17, 2023

View reviewed changes

Merge remote-tracking branch 'origin/main' into jacob/no-map-type-arg…

a8588b8

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vercel bot deployed to Preview October 18, 2023 16:13 View deployment

jtbandes merged commit 170ef5a into main Oct 23, 2023
13 of 14 checks passed

jtbandes deleted the jacob/no-map-type-argument branch October 23, 2023 16:40

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Add lint rule to prefer `map((): T => {})` over `map<T>(() => {})` #6995

Add lint rule to prefer `map((): T => {})` over `map<T>(() => {})` #6995

jtbandes commented Oct 14, 2023 •

edited

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Add lint rule to prefer map((): T => {}) over map<T>(() => {}) #6995

Add lint rule to prefer map((): T => {}) over map<T>(() => {}) #6995

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Add lint rule to prefer `map((): T => {})` over `map<T>(() => {})` #6995

Add lint rule to prefer `map((): T => {})` over `map<T>(() => {})` #6995

jtbandes commented Oct 14, 2023 •

edited

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