Why does null equal undefined?
The undefined value is a primitive value used when a variable has not been assigned a value. The null value is a primitive value that represents the null, empty, or non-existent reference. When you declare a variable through var and do not give it a value, it will have the value undefined.
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. Because of that, the next statement will return false, as the === comparison operator checks both the types and their value.
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.
Does null == undefined?
null is an assigned value. It means nothing. undefined means a variable has been declared but not defined yet.
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.
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.
What is the difference between NULL & undefined?
Many times we often get confused on what the difference between UNDEFINED and NULL is. Simply put, undefined means a variable has been declared but has not yet been assigned a value. … On the other hand, null is an object. It can be assigned to a variable as a representation of no value.
What is difference between NULL and NULL?
Null has a default value 0. it can be used as bool,integer, pointer. But C# null is used when we are not pointing to some object. I am not sure whether null can be used in place of NULL in C#.
Is null or undefined Lodash?
Lodash helps in working with arrays, strings, objects, numbers, etc. The _. isNil() method is used to check if the value is null or undefined. If the value is nullish then returns true otherwise it returns false.