Expected '!==' and instead saw '!='
31 },
32 );
33
34 if (integrationIds.length != 1) {35 throw new NoIntegrationSelectedError();
36 }
37
Description
It is considered good practice to use the type-safe equality operators ===
and !==
instead of their regular counterparts ==
and !=
.
The strict equality operators (===
and !==
) use the strict equality comparison algorithm to compare two operands.
- If the operands are of different types, return
false
. - If both operands are objects, return
true
only if they refer to the same object. - If both operands are
null
or both operands areundefined
, returntrue
. - If either operand is
NaN
, returnfalse
. - Otherwise, compare the two operand's values:
- Numbers must have the same numeric values.
+0
and-0
are considered to be the same value. - Strings must have the same characters in the same order.
- Booleans must be both
true
or bothfalse
.
- Numbers must have the same numeric values.
The most notable difference between this operator and the equality (==
) operator is that if the operands are of different types, the ==
operator attempts to convert them to the same type before comparing.
Bad Practice
a == b
foo == true
bananas != 1
value == undefined
typeof foo == 'undefined'
'hello' != 'world'
0 == 0
true == true
foo == null
Recommended
a === b
foo === true
bananas !== 1
value === undefined
typeof foo === 'undefined'
'hello' !== 'world'
0 === 0
true === true
foo === null