Is null or empty in JavaScript?

Is null or empty string JavaScript?

Use the === Operator to Check if the String Is Empty in JavaScript. We can use the strict equality operator ( === ) to check whether a string is empty or not. The comparison data===”” will only return true if the data type of the value is a string, and it is also empty; otherwise, return false .

Is there null in JavaScript?

The null type is the second primitive data type that also has only one value: null . JavaScript defines that null is equal to undefined as shown in the following statement.

Is null or empty?

So, in review: Null means the variable does not exist. Empty means it exists, but it contains no value. Zero length means an array or similar structure has been declared — and, if the language is strongly typed, has type — but contains no values.

Is null or undefined JavaScript?

Null: It is the intentional absence of the value. It is one of the primitive values of JavaScript. Undefined: It means the value does not exist in the compiler. It is the global object.

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How do you check if a string is null?

Given a string str, the task is to check if this string is null or not, in Java.


  1. Get the String to be checked in str.
  2. We can simply compare the string with Null using == relational operator. Syntax: if(str == null)
  3. Print true if the above condition is true. Else print false.

Is null and empty string the same?

An empty string is a string instance of zero length, whereas a null string has no value at all. An empty string is represented as “” . It is a character sequence of zero characters.

Is null a data type?

Null is a special data type which can have only one value: NULL. A variable of data type NULL is a variable that has no value assigned to it.

IS NOT null check in JavaScript?

You can easily check if a variable Is Null or Not Null in JavaScript by applying simple if-else condition to the given variable.

  • If my_var is undefined then the condition will execute.
  • If my_var is 0 then the condition will execute.
  • If my_var is ” (empty string) then the condition will execute.

IS NOT NULL in VBScript?

The IsNull function returns a Boolean value that indicates whether a specified expression contains no valid data (Null). It returns True if expression is Null; otherwise, it returns False.

Is an empty list null?

An empty collection isn’t the same as null . An empty collection is actually a collection, but there aren’t any elements in it yet. null means no collection exists at all.

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Is null or empty VBScript?

To check if a string is empty in VBScript, you can use the function Len. Both message boxes will be shown. A String in VBScript can’t be set to Null. An unset String in VBScript has a value of “” and contains no characters.

Is it better to return null or undefined?

Undefined typically refers to something which has not yet been assigned a value (yet). Null refers to something which definitively has no value. In that case, I would recommend returning a null. Note that a function with no specified return value implicitly returns undefined.

Does undefined check for null?

To check if a variable is not given a value, you would only need to check against undefined and null. This is assuming 0 , “” , and objects(even empty object and array) are valid “values”.