Enforce the use of === and !==
TRY THIS RULE ID: typescript-code-style/strict-equals
Language: TypeScript
Severity: Notice
Category: Best Practices
Description In JavaScript, == and != comparisons do type coercion, which can be confusing and may introduce potential errors. Use the type-safe equality operators === and !== instead.
Non-Compliant Code Examples a == b
a != b
typeof a == 'number'
typeof a == 'number'
'string' != typeof a
true == true
2 == 3
2 == 3
'hello' != 'world'
'hello' != 'world'
a == null
a == null
null != a
true == 1
0 != '1'
'wee' == /wee/
typeof a == 'number'
'string' != typeof a
'hello' != 'world'
2 == 3
true == true
true == null
true != null
null == null
null != null
a
==
b
( a ) == b
( a ) != b
a == ( b )
a != ( b )
( a ) == ( b )
( a == b ) == ( c )
( a != b ) != ( c )
a == b ;
a != b ;
( a + b ) == c ;
( a + b ) != c ;
(( 1 ) ) == ( 2 );
Compliant Code Examples a === b
a !== b
a === b
a !== null
a === null
a !== null
null === null
null !== null
// https://github.com/eslint/eslint/issues/8020
foo === /abc/u
// bigint
foo === 1 n
foo != undefined
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