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prefer-ts-extras-array-find

Prefer arrayFind from ts-extras over array.find(...).

arrayFind(...) improves predicate inference and value narrowing in typed arrays.

Targeted pattern scopeโ€‹

This rule focuses on direct array.find(predicate) calls that can be migrated to arrayFind(array, predicate) with deterministic fixes.

  • array.find(predicate) call sites that can use arrayFind(array, predicate).

Alias indirection, wrapper helpers, and non-canonical call shapes are excluded to keep arrayFind(array, predicate) migrations safe.

What this rule reportsโ€‹

This rule reports array.find(predicate) call sites when arrayFind(array, predicate) is the intended replacement.

  • array.find(predicate) call sites that can use arrayFind(array, predicate).

Why this rule existsโ€‹

arrayFind keeps predicate-driven lookup aligned with the other ts-extras helper APIs and improves inference in generic code.

  • Predicate call sites are standardized across modules.
  • Result types are easier to follow in utility layers.
  • Local type assertions after find calls are reduced.

โŒ Incorrectโ€‹

const monitor = monitors.find((entry) => entry.id === targetId);

โœ… Correctโ€‹

const monitor = arrayFind(monitors, (entry) => entry.id === targetId);

Behavior and migration notesโ€‹

  • Runtime behavior matches native Array.prototype.find.
  • Search still returns the first matching element.
  • If no element matches, the result is undefined.

Additional examplesโ€‹

โŒ Incorrect โ€” Additional exampleโ€‹

const user = users.find((item) => item.id === userId);

โœ… Correct โ€” Additional exampleโ€‹

const user = arrayFind(users, (item) => item.id === userId);

โœ… Correct โ€” Repository-wide usageโ€‹

const firstError = arrayFind(logs, (entry) => entry.level === "error");

ESLint flat config exampleโ€‹

import typefest from "eslint-plugin-typefest";

export default [
    {
        plugins: { typefest },
        rules: {
            "typefest/prefer-ts-extras-array-find": "error",
        },
    },
];

When not to use itโ€‹

Disable this rule if your team requires native .find() for consistency with existing shared APIs.

Package documentationโ€‹

ts-extras package documentation:

ts-extras@0.17.x does not currently expose arrayFind in its published API, so there is no canonical source/*.ts link for this helper yet.

Reference links:

Rule catalog ID: R003

Further readingโ€‹

Adoption resourcesโ€‹