JavaScript handler.deleteProperty() Method

The handler.deleteProperty() method in JavaScript is a trap for the delete operator. This method returns the boolean value if the delete was successful.

Syntax:

const p = new Proxy(target, {
  deleteProperty: function(target, property) {
  }
});

Parameters: This method accepts two parameters as mentioned above and described below: 

• Target: This parameter holds the target object.
• Property: This parameter holds the name of the property which is to be deleted.

Return value: This method returns a Boolean value which indicates whether the property was successfully deleted.

The below examples illustrate the handler.deleteProperty() method in JavaScript:

Example 1: In this example, we will trap a delete operator using the handler.deleteProperty() method in JavaScript.

javascript

<script>
    const monster1 = {
      Color: 'Green'
    };

    const handler1 = {
      deleteProperty(target, prop) {
        if (prop in target) {
          delete target[prop];
          console.log(`${prop} is property which is removed`);
        }
      }
    };

    console.log(monster1.Color);

    const proxy1 = new Proxy(monster1, handler1);
    delete proxy1.Color;

    console.log(monster1.Color);

    var f = { bar: 'baz' }
    console.log('bar' in f)

    delete f.bar
    console.log('bar' in f)
</script>

Output:

"Green"
"Color is property which is removed"
undefined
true
false

Example 2: In this example, we will trap a delete operator using the handler.deleteProperty() method in JavaScript.

javascript

<script>
    const obj = new Proxy({}, {
      deleteProperty: function(target, prop) {
        if (prop in target){
          delete target[prop]
          console.log(prop+ ' property is removed.')
          return true
        }
        else {
          console.log(prop+ ' property is not removed.')
          return false
        }
      }
    })

    let result

    obj.prop1 = 10
    console.log('prop1' in obj)

    result = delete obj.prop1
    console.log(result)
    console.log('prop1' in obj)

    result = delete obj.prop1
    console.log(result)
</script>

Output:

true
"prop1 property is removed."
true
false
"prop1 property is not removed."
false

We have a complete list of Javascript Functions, to check those go through the Javascript Functions Complete Reference article.

Supported Browsers: The browsers supported by the handler.deleteProperty() method are listed below: 

• Google Chrome 49 and above
• Edge 12 and above
• Firefox 18 and above
• Opera 36 and above
• Safari  10 and above