5/19/2023 0 Comments Javascript null check![]() We can also add null as an item to the array. In Javascript, we can pass null as a valid argument to the function. That means checking for null is one of the few times in JavaScript that using = (double equality operator)is recommended, while otherwise = (strict comparison operator) is generally recommended. Therefore, it is better to handle null and undefined values, as both represent the absence of a value. Now, you can see that null is not strictly equal to undefined. Is null strict equal to empty: false Is null strict equal to zero: false Is null strict equal to false: false Is null strict equal to NaN: false Is null strict equal to 0n: false Is null strict equal to null: true Is null strict equal to undefined: false ![]() Now, check all the values above against the null with (=) strict equal to the operator. If we have to ensure that we have precisely the null value, excluding any undefined values, using a triple equality = operator will do the trick. Checking null values using triple equality(=) operator In fact, the only values that null is loosely equal to are undefined(undefined = null) and itself(null = null) because both return true. But when it comes to null = null, it returns true. Then we checked against the NaN value, which is not equal to null either. Thus, despite the hard fact that null is a falsy value (i.e., it evaluates to false if coerced to a boolean), it still is not considered loosely equal to any of the other falsy values in JavaScript. Then null is not equal to zero, and null is not equal to a false boolean value, although it is a falsy value it is not equal to false. ![]() ![]() ![]() In the above example, we have checked the null value against some of the most unexpected and erroneous values, and we have got the output, and some of them are still unexpected to us.įirst, null in Javascript is not equal to empty. Is null equal to empty: false Is null equal to zero: false Is null equal to false: false Is null equal to NaN: false Is null equal to 0n: false Is null equal to null: true Is null equal to undefined: true ![]()
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