Working with objects is an essential component of creating apps with JavaScript. Whether it’s to clean up data or get an object ready for a particular use case, you may frequently need to delete properties from an object. This article examines several methods for deleting properties from a JavaScript object, going over each one’s benefits and drawbacks. We’ll also go over how to effectively remove several properties from a single object.
1. Using the delete Operator
The delete operator is the simplest method for deleting a property from a JavaScript object. Although this operator is simple and easy to use, developers should be aware of some of its limitations.
const employee= {
name: 'John Doe',
age: 33,
job: 'Manager'
}
delete employee.age
console.log(employee) // Output: { name: 'John Doe', job: 'Manager' }A JavaScript object’s given property can be deleted using the delete operator. The property can no longer be accessed within the original object after deletion. However, if a property is present in the prototype, it can still be accessed because the delete operator has no effect on the object’s prototype chain.
While the delete operator is easy to use, it has a few downsides:
- Performance Problems: In applications where performance is crucial, the delete operator may result in a decline in performance. JavaScript engines optimize objects for speed; nevertheless, de-optimization may occur if a property is removed.
- Mutating Objects: By eliminating the designated property, the delete operator modifies the original object. Unexpected side effects may result from this, particularly when working with shared objects in a global scope.
2. Setting the Property to undefined or null
Setting a property’s value to undefined or null is an additional method for eliminating properties from a JavaScript object. This shows that the property has no value but does not physically delete it from the object.
const employee= {
name: 'John Doe',
age: 33,
job: 'Manager'
}
employee.age = undefined
console.log(employee) // Output: { name: 'John Doe', age: undefined, job: 'Manager' }Differences Between undefined and null
Undefined: Indicates a property or variable that has not yet been given a value.null: Indicates that there is no object value present on purpose.
When you wish to communicate that a property has no value but yet need to preserve the original object’s structure, this method can be helpful. When a property is set to null or undefined, it indicates that the property is still present in the object. If other sections of your code require the property to be totally absent, this could cause confusion.
