Rule proposal: no-instanceof-builtin-object
Description
instanceof operator in JavaScript has some limitations.
To detect the type of a variable, we should encourage user to use:
typeofoperator
typeof foo === 'string' // detect whether foo is stringnode:util/typesmodule (for Node)
import {isNumberObject, isMap} from 'node:util/types';
isNumberObject(new Number(123)) // true
isNumberObject(123) // false
isMap(new Map()) // true@sindresorhus/ismodule (for browser)
import is from '@sindresorhus/is';
is(new Map()) === 'Map' // trueTherefore, builtin objects like Map/Promise/Error can be detected by typeof, node:util/types and @sindresorhus/is. Should not use instanceof.
Rule no-instanceof-array can be removed if this rule is implemented.
Fail
foo instanceof Array
foo instanceof Map
foo instanceof PromisePass
import types from 'node:util/types'
Array.isArray(foo)
types.isMap(foo)
types.isPromise(foo)import is from '@sindresorhus/is'
is(foo) === 'Array'
is(foo) === 'Map'
is(foo) === 'Promise'Proposed rule name
no-instanceof-builtin-object
Additional Info
No response
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