What is the use of Delete in JavaScript?

In JavaScript, the delete operator is employed to delete a property of an object. After deleting the actual property, that property won’t be accessible and returns undefined . The invocation of the delete operator returns true when it removes a property and false otherwise.

What is the purpose of the delete keyword?

The purpose of the delete operator is to completely remove a property from an object, whereas setting a property to undefined just sets the property to undefined .

Is JavaScript delete bad?

2 Answers. No, it’s not considered bad practice.

Is delete a keyword in JavaScript?

The delete keyword deletes both the value of the property and the property itself. After deletion, the property cannot be used before it is added back again. The delete operator is designed to be used on object properties. It has no effect on variables or functions.

What is a delete operator?

Delete Operator in C++ A delete operator is used to deallocate memory space that is dynamically created using the new operator, calloc and malloc() function, etc., at the run time of a program in C++ language.

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How do you use Delete?

Delete is an operator that is used to destroy array and non-array(pointer) objects which are created by new expression.

  1. Delete can be used by either using Delete operator or Delete [ ] operator.
  2. New operator is used for dynamic memory allocation which puts variables on heap memory.

Does delete return any value?

Does delete return any value? Explanation: The delete operator doesn’t return any value. Its function is to delete the memory allocated for an object. This is done in reverse way as that new operator works.

What happens when delete is used for a null pointer?

What happens when delete is used for a NULL pointer? Question 4 Explanation: Deleting a null pointer has no effect, so it is not necessary to check for a null pointer before calling delete.

Is delete a unary operator JavaScript?

An operator is a symbol or sign that maps operands to output values. A unary operation is an operation with only one operand.


Operator Explanation
delete Deletes specific index of an array or specific property of an object
void Discards a return value of an expression.

What are JavaScript data types?

JavaScript types

  • Primitive values (immutable datum represented directly at the lowest level of the language) Boolean type. Null type. Undefined type. Number type. BigInt type. String type. Symbol type.
  • Objects (collections of properties)

How do you delete in Java?

There is no delete in java, and all objects are created on the heap. The JVM has a garbage collector that relies on reference counts. Once there are no more references to an object, it becomes available for collection by the garbage collector.

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How do you delete an object key?

Use delete to Remove Object Keys

The special JavaScript keyword delete is used to remove object keys (also called object properties). While you might think setting an object key equal to undefined would delete it, since undefined is the value that object keys that have not yet been set have, the key would still exist.

How do you delete an object in node JS?


  1. Use the Delete Method.
  2. Set Property Value to Undefined, Null, or False.
  3. Use Object.keys() to Remove Without Mutation.

When to use delete and delete []?

Using delete will only delete one single object. In the code above, we have an array of objects, thus the right way to delete those objects is by using delete []. So when you have a single object you use delete. When you have an array of objects you need to use delete[] as shown in the example below.

Is it safe to delete Nullptr?

In c++03 it is pretty clear that deleting a null pointer has no effect. Indeed, it is explicitly stated in §5.3. 5/2 that: In either alternative, if the value of the operand of delete is the null pointer the operation has no effect.

What happens if delete p is called when p is null?

No! The C++ language guarantees that delete p will do nothing if p is null. Since you might get the test backwards, and since most testing methodologies force you to explicitly test every branch point, you should not put in the redundant if test.

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