useExhaustiveDependencies (since v1.0.0)

Diagnostic Category: lint/correctness/useExhaustiveDependencies

Sources:

Same as: react-hooks/exhaustive-deps

Enforce all dependencies are correctly specified in a React hook.

This rule is a port of the rule react-hooks/exhaustive-deps, and it’s meant to target projects that uses React.

If your project doesn’t use React (or Preact), you shouldn’t use this rule.

The rule will inspect the following known hooks:

useEffect
useLayoutEffect
useInsertionEffect
useCallback
useMemo
useImperativeHandle
useState
useReducer
useRef
useDebugValue
useDeferredValue
useTransition

If you want to add more hooks to the rule, check the options.

Examples

Invalid

import { useEffect } from "react";

function component() {
    let a = 1;
    useEffect(() => {
        console.log(a);
    }, []);
}

correctness/useExhaustiveDependencies.js:5:5 lint/correctness/useExhaustiveDependencies ━━━━━━━━━━━━

  ✖ This hook does not specify all of its dependencies: a
  
    3 │ function component() {
    4 │     let a = 1;
  > 5 │     useEffect(() => {
      │     ^^^^^^^^^
    6 │         console.log(a);
    7 │     }, []);
  
  ℹ This dependency is not specified in the hook dependency list.
  
    4 │     let a = 1;
    5 │     useEffect(() => {
  > 6 │         console.log(a);
      │                     ^
    7 │     }, []);
    8 │ }
  
  ℹ Either include it or remove the dependency array

import { useEffect } from "react";

function component() {
    let b = 1;
    useEffect(() => {
    }, [b]);
}

correctness/useExhaustiveDependencies.js:5:5 lint/correctness/useExhaustiveDependencies ━━━━━━━━━━━━

  ✖ This hook specifies more dependencies than necessary: b
  
    3 │ function component() {
    4 │     let b = 1;
  > 5 │     useEffect(() => {
      │     ^^^^^^^^^
    6 │     }, [b]);
    7 │ }
  
  ℹ This dependency can be removed from the list.
  
    4 │     let b = 1;
    5 │     useEffect(() => {
  > 6 │     }, [b]);
      │         ^
    7 │ }
    8 │

import { useEffect, useState } from "react";

function component() {
    const [name, setName] = useState();
    useEffect(() => {
        console.log(name);
        setName("");
    }, [name, setName]);
}

correctness/useExhaustiveDependencies.js:5:5 lint/correctness/useExhaustiveDependencies ━━━━━━━━━━━━

  ✖ This hook specifies more dependencies than necessary: setName
  
    3 │ function component() {
    4 │     const [name, setName] = useState();
  > 5 │     useEffect(() => {
      │     ^^^^^^^^^
    6 │         console.log(name);
    7 │         setName("");
  
  ℹ This dependency can be removed from the list.
  
     6 │         console.log(name);
     7 │         setName("");
   > 8 │     }, [name, setName]);
       │               ^^^^^^^
     9 │ }
    10 │

import { useEffect } from "react";

function component() {
    let a = 1;
    const b = a + 1;
    useEffect(() => {
        console.log(b);
    }, []);
}

correctness/useExhaustiveDependencies.js:6:5 lint/correctness/useExhaustiveDependencies ━━━━━━━━━━━━

  ✖ This hook does not specify all of its dependencies: b
  
    4 │     let a = 1;
    5 │     const b = a + 1;
  > 6 │     useEffect(() => {
      │     ^^^^^^^^^
    7 │         console.log(b);
    8 │     }, []);
  
  ℹ This dependency is not specified in the hook dependency list.
  
    5 │     const b = a + 1;
    6 │     useEffect(() => {
  > 7 │         console.log(b);
      │                     ^
    8 │     }, []);
    9 │ }
  
  ℹ Either include it or remove the dependency array

Valid

import { useEffect } from "react";

function component() {
    let a = 1;
    useEffect(() => {
        console.log(a);
    }, [a]);
}

import { useEffect } from "react";

function component() {
    const a = 1;
    useEffect(() => {
        console.log(a);
    });
}

import { useEffect, useState } from "react";

function component() {
    const [name, setName] = useState();
    useEffect(() => {
        console.log(name);
        setName("");
    }, [name]);
}

import { useEffect } from "react";
let outer = false;
function component() {
    useEffect(() => {
        outer = true;
    }, []);
}

Options

Allows to specify custom hooks - from libraries or internal projects - for which dependencies should be checked and/or which are known to have stable return values.

Validating dependencies

For every hook for which you want the dependencies to be validated, you should specify the index of the closure and the index of the dependencies array to validate against.

Example

{
    "//": "...",
    "options": {
        "hooks": [
            { "name": "useLocation", "closureIndex": 0, "dependenciesIndex": 1},
            { "name": "useQuery", "closureIndex": 1, "dependenciesIndex": 0}
        ]
    }
}

Given the previous example, your hooks can be used like this:

function Foo() {
    const location = useLocation(() => {}, []);
    const query = useQuery([], () => {});
}

Stable results

When a hook is known to have a stable return value (its identity doesn’t change across invocations), that value doesn’t need to be specified in dependency arrays. For example, setters returned by React’s useState hook always have the same identity and should be omitted as such.

You can configure custom hooks that return stable results in one of three ways:

"stableResult": true — marks the return value as stable. An example of a React hook that would be configured like this is useRef().
"stableResult": [1] — expects the return value to be an array and marks the given index or indices to be stable. An example of a React hook that would be configured like this is useState().
"stableResult": 1 — shorthand for "stableResult": [1].

Example

{
    "//": "...",
    "options": {
        "hooks": [
            { "name": "useDispatch", "stableResult": true }
        ]
    }
}

With this configuration, the following is valid:

const dispatch = useDispatch();
// No need to list `dispatch` as dependency:
const doAction = useCallback(() => dispatch(someAction()), []);

Preact support

This rule recognizes rules imported from preact/compat and preact/hooks and applies the same rules as for React hooks.

useExhaustiveDependencies (since v1.0.0)

Examples

Invalid

Valid

Options

Validating dependencies

Example

Stable results

Example

Preact support

Related links