Is null == undefined?

It means null is equal to undefined but not identical. When we define a variable to undefined then we are trying to convey that the variable does not exist . When we define a variable to null then we are trying to convey that the variable is empty.

Is null == undefined true?

Both undefined and null are falsy by default. So == returns true. But when we use the strict equality operator (===) which checks both type and value, since undefined and null are of different types (from the typeof Operator section), the strict equality operator returns false.

Is null == undefined in JavaScript?

In JavaScript, undefined is a type, whereas null an object. It means a variable declared, but no value has been assigned a value. Whereas, null in JavaScript is an assignment value.

Why is null == undefined true in JavaScript?

The == comparison operator doesn't check the types. null and undefined both return false . That's why your code is actually checking if false is equal to false . However their types are not equal.

Is null and undefined the same thing?

null is an assigned value. It means nothing. undefined typically means a variable has been declared but not defined yet. null and undefined are falsy values.

Are You Using Null And Undefined Wrong?

What is == and === in JavaScript?

= is used for assigning values to a variable in JavaScript. == is used for comparison between two variables irrespective of the datatype of variable. === is used for comparision between two variables but this will check strict type, which means it will check datatype and compare two values.

Why we use === in JavaScript?

The === operator compares operands and returns true if both operands are of same data type and have some value, otherwise, it returns false. The !== operator compares operands and returns true if both operands are of different data types or are of the same data type but have different values.

Is null True or false?

The value null is a JavaScript literal represents an "empty" value or "undefined". null is one of JavaScript's primitive values. It is neither equal to boolean true nor equal to boolean false because it's value is undefined. The value of null is more inclined towards false even though it is not false .

Is NaN equal null?

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 we have checked against the NaN value, which is not equal to null either.

Should I use null or undefined?

Only use null if you explicitly want to denote the value of a variable as having "no value". As @com2gz states: null is used to define something programmatically empty. undefined is meant to say that the reference is not existing. A null value has a defined reference to "nothing".

What is the difference between the operators == & ===?

Difference between == and === operator in JavaScript

No. Double equals named as Equality Operator. Triple equals named as Identity / Strict equality Operator. Triple equals used as Strict conversion without performing any conversion in operands.

Why does JavaScript have both null and undefined?

Just like numbers and characters, `null` has a specific configuration of 1's and 0's that indicates it's type is `null` and that it's value is `null`. Same with `undefined`. These are used in JavaScript to act as placeholders to let the programmer know when a variable has no value.

Should I return null or undefined?

Generally, if you need to assign a non-value to a variable or property, pass it to a function, or return it from a function, null is almost always the best option. To put it simply, JavaScript uses undefined and programmers should use null .

Does undefined equal undefined?

#735.

Is undefined equal to itself?

JavaScript probably tries to convert them to some comparable values, e.g. a number. But undefined converted to a number is NaN, which is neither equal to itself nor greater than itself. It's Javascript.

Why is NaN === NaN false?

Although either side of NaN===NaN contains the same value and their type is Number but they are not same. According to ECMA-262, either side of == or === contains NaN then it will result false value.

Why is isNaN null false?

Example. The isNaN(null) == false is semantically correct. This is because null is not NaN.

Is NaN a none?

nan allows for vectorized operations; its a float value, while None , by definition, forces object type, which basically disables all efficiency in numpy.

IS null == false in Java?

You can't compare null to a boolean . They are different types one indicating a null reference pointer and the other a false/not true value. Thus the answer is: No this expression is not even valid (and if it was, it would be false).

IS null == false C#?

The way you typically represent a “missing” or “invalid” value in C# is to use the “null” value of the type. Every reference type has a “null” value; that is, the reference that does not actually refer to anything.

Is null a valid Boolean?

A null Boolean means that the variable has no reference assigned, so it is neither true nor false, it is “nothing”.

What does == mean in JS?

The === operator means "is exactly equal to," matching by both value and data type. The == operator means "is equal to," matching by value only.

Which is faster == or === in JavaScript?

So === faster than == in Javascript

=== compares if the values and the types are the same. == compares if the values are the same, but it also does type conversions in the comparison. Those type conversions make == slower than ===.

Why === is false in JavaScript?

Because == (and === ) test to see if two objects are the same object and not if they are identical objects.

What does === mean in coding?

What does === triple equal means. Just like double equal operator === also used to compare two values on left and right. This will also return true or false based on comparison. Triple equal operator is also common used in if else conditions, while loops and some other places in code.