arrayIncludesMethods

Reports using Array#some() with simple equality checks that can be replaced with .includes().

✅ This rule is included in the ts stylistic and stylisticStrict presets.

Array.prototype.some() is intended for more complex predicate checks. When the callback only performs a simple equality check (x === value or x == value), .includes() is more readable and expressive.

This rule reports when .some() can be simplified to .includes().

declare const 
const array: string[]
array: string[];
const array: string[]
array.
Array<string>.some(predicate: (value: string, index: number, array: string[]) => unknown, thisArg?: any): boolean
Determines whether the specified callback function returns true for any element of an array.
@param ― predicate A function that accepts up to three arguments. The some method calls
the predicate function for each element in the array until the predicate returns a value
which is coercible to the Boolean value true, or until the end of the array.
@param ― thisArg An object to which the this keyword can refer in the predicate function.
If thisArg is omitted, undefined is used as the this value.
some((
item: string
item) => 
item: string
item === "value");

declare const 
const array: string[]
array: string[];
const array: string[]
array.
Array<string>.some(predicate: (value: string, index: number, array: string[]) => unknown, thisArg?: any): boolean
Determines whether the specified callback function returns true for any element of an array.
@param ― predicate A function that accepts up to three arguments. The some method calls
the predicate function for each element in the array until the predicate returns a value
which is coercible to the Boolean value true, or until the end of the array.
@param ― thisArg An object to which the this keyword can refer in the predicate function.
If thisArg is omitted, undefined is used as the this value.
some((
item: string
item) => "value" === 
item: string
item);

declare const 
const array: number[]
array: number[];
declare const 
const target: number
target: number;
const array: number[]
array.
Array<number>.some(predicate: (value: number, index: number, array: number[]) => unknown, thisArg?: any): boolean
Determines whether the specified callback function returns true for any element of an array.
@param ― predicate A function that accepts up to three arguments. The some method calls
the predicate function for each element in the array until the predicate returns a value
which is coercible to the Boolean value true, or until the end of the array.
@param ― thisArg An object to which the this keyword can refer in the predicate function.
If thisArg is omitted, undefined is used as the this value.
some((
element: number
element) => 
element: number
element === 
const target: number
target);

declare const 
const array: string[]
array: string[];
const array: string[]
array.
Array<string>.some(predicate: (value: string, index: number, array: string[]) => unknown, thisArg?: any): boolean
Determines whether the specified callback function returns true for any element of an array.
@param ― predicate A function that accepts up to three arguments. The some method calls
the predicate function for each element in the array until the predicate returns a value
which is coercible to the Boolean value true, or until the end of the array.
@param ― thisArg An object to which the this keyword can refer in the predicate function.
If thisArg is omitted, undefined is used as the this value.
some(function (
item: string
item) {
  return 
item: string
item === "value";
});

declare const 
const array: string[]
array: string[];
const array: string[]
array.
Array<string>.includes(searchElement: string, fromIndex?: number): boolean
Determines whether an array includes a certain element, returning true or false as appropriate.
@param ― searchElement The element to search for.
@param ― fromIndex The position in this array at which to begin searching for searchElement.
includes("value");

declare const 
const array: string[]
array: string[];
const array: string[]
array.
Array<string>.some(predicate: (value: string, index: number, array: string[]) => unknown, thisArg?: any): boolean
Determines whether the specified callback function returns true for any element of an array.
@param ― predicate A function that accepts up to three arguments. The some method calls
the predicate function for each element in the array until the predicate returns a value
which is coercible to the Boolean value true, or until the end of the array.
@param ― thisArg An object to which the this keyword can refer in the predicate function.
If thisArg is omitted, undefined is used as the this value.
some((
item: string
item) => 
item: string
item.
String.startsWith(searchString: string, position?: number): boolean
Returns true if the sequence of elements of searchString converted to a String is the
same as the corresponding elements of this object (converted to a String) starting at
position. Otherwise returns false.
startsWith("v"));

declare const 
const array: number[]
array: number[];
const array: number[]
array.
Array<number>.some(predicate: (value: number, index: number, array: number[]) => unknown, thisArg?: any): boolean
Determines whether the specified callback function returns true for any element of an array.
@param ― predicate A function that accepts up to three arguments. The some method calls
the predicate function for each element in the array until the predicate returns a value
which is coercible to the Boolean value true, or until the end of the array.
@param ― thisArg An object to which the this keyword can refer in the predicate function.
If thisArg is omitted, undefined is used as the this value.
some((
item: number
item) => 
item: number
item > 0);

declare const 
const array: object[]
array: object[];
const array: object[]
array.
Array<object>.some(predicate: (value: object, index: number, array: object[]) => unknown, thisArg?: any): boolean
Determines whether the specified callback function returns true for any element of an array.
@param ― predicate A function that accepts up to three arguments. The some method calls
the predicate function for each element in the array until the predicate returns a value
which is coercible to the Boolean value true, or until the end of the array.
@param ― thisArg An object to which the this keyword can refer in the predicate function.
If thisArg is omitted, undefined is used as the this value.
some((
item: object
item) => 
item: object
item.id === 1);Error ts(2339)  ― Property 'id' does not exist on type 'object'.

Options

This rule is not configurable.

When Not To Use It

If your codebase uses .some() for consistency even with simple equality checks, or if you have a large number of existing uses that would be difficult to refactor, you might prefer to disable this rule.

Equivalents in Other Linters

ESLint: unicorn/prefer-includes

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arrayIncludesMethods

Examples

Options

When Not To Use It

Further Reading

Equivalents in Other Linters