Question

When do you use null instead of undefined?

Answer 1

In JavaScript, 'null' represents an intentional absence of any value and is assigned by the programmer, whereas 'undefined' indicates that a variable has been declared but not assigned a value and is generally assigned by the JavaScript engine.

Step-by-step explanation:

In the context of JavaScript, null and undefined are two different types that represent the absence of a value. You use null when you want to intentionally indicate that a variable is empty or does not have a value. It is often used in programming to represent a 'nothing' or 'no value' state, and you would typically assign it to a variable explicitly.

Undefined, on the other hand, is used by JavaScript to indicate that a variable has been declared but has not yet been assigned a value. It can be considered a default uninitialized state. You would see undefined in situations where an object property does not exist, or a function does not explicitly return a value.

To summarize, use null as a deliberate assignment to signify 'no value', and undefined typically pops up by default when JavaScript encounters an unassigned or undeclared state.

Answer 2

In JavaScript, 'null' represents an intentional absence of any value and is assigned by the programmer, whereas 'undefined' indicates that a variable has been declared but not assigned a value and is generally assigned by the JavaScript engine.

Step-by-step explanation:

In the context of JavaScript, null and undefined are two different types that represent the absence of a value. You use null when you want to intentionally indicate that a variable is empty or does not have a value. It is often used in programming to represent a 'nothing' or 'no value' state, and you would typically assign it to a variable explicitly.

Undefined, on the other hand, is used by JavaScript to indicate that a variable has been declared but has not yet been assigned a value. It can be considered a default uninitialized state. You would see undefined in situations where an object property does not exist, or a function does not explicitly return a value.

To summarize, use null as a deliberate assignment to signify 'no value', and undefined typically pops up by default when JavaScript encounters an unassigned or undeclared state.