==
and !=
JS-0050 14var __importStar = (this && this.__importStar) || function (mod) {
15 if (mod && mod.__esModule) return mod;
16 var result = {};
17 if (mod != null) for (var k in mod) if (k !== "default" && Object.hasOwnProperty.call(mod, k)) __createBinding(result, mod, k); 18 __setModuleDefault(result, mod);
19 return result;
20};
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.
false
.true
only if they refer to the same object.null
or both operands are undefined
, return true
.NaN
, return false
.+0
and -0
are considered to be the same value.true
or both false
.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.
a == b
foo == true
bananas != 1
value == undefined
typeof foo == 'undefined'
'hello' != 'world'
0 == 0
true == true
foo == null
a === b
foo === true
bananas !== 1
value === undefined
typeof foo === 'undefined'
'hello' !== 'world'
0 === 0
true === true
foo === null