Avoid use of
== and != JS-0050
Anti-pattern
Minor
11 days ago
—
11 days old
Expected '===' and instead saw '=='
48 <div key={item.id}>
49 <Link onClick={() => setSelected(item.value)} to={item.value}>
50 <li
51 className={`p-4 hover:bg-gray-600 cursor-pointer ${item.value == selected ? 'bg-gray-600' : ''}`}52 >
53 <div>{item.name}</div>
54 </li>Expected '!==' and instead saw '!='
1009 }
1010
1011 if (
1012 req.body.state != undefined &&1013 (req.body.state === 'EDIT' || req.body.state === 'REVIEW')
1014 )
1015 update.state = req.body.state;Expected '===' and instead saw '=='
118 detail.customFields.length &&
119 vulnerability.customFields.every((e, idx) => {
120 return (
121 e.customField._id == detail.customFields[idx].customField &&122 e.text === detail.customFields[idx].text
123 );
124 })Expected '===' and instead saw '=='
378
379// Upercases input: {input | upper}
380expressions.filters.upper = function (input) {
381 if (!input || input == 'undefined') return input;382 return input.toUpperCase();
383};
384Expected '===' and instead saw '=='
367
368// Capitalizes input first letter of each word, can be associated to 'lower' to normalize case: {creator.lastname | lower | title}
369expressions.filters.title = function (input) {
370 if (!input || input == 'undefined') return input;371 return input.replace(/\w\S*/g, w => w.replace(/^\w/, c => c.toUpperCase()));
372};
373
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
trueonly if they refer to the same object. - If both operands are
nullor both operands areundefined, returntrue. - If either operand is
NaN, returnfalse. - Otherwise, compare the two operand's values:
- Numbers must have the same numeric values.
+0and-0are considered to be the same value. - Strings must have the same characters in the same order.
- Booleans must be both
trueor 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