README.md

Delete

Execute this code:

var name = 'John',
    obj = {
        name: 'James'
    },
    Animal,
    mammal;

Animal = function(){};
Animal.prototype.name = 'animal';

mammal = new Animal();
mammal.name = 'mammal';

delete name;

console.log('#1: ' + name);

delete obj.name;

console.log('#2: ' + obj.name);

delete obj.toString;

console.log('#3: ' + obj.toString);

delete mammal.name;

console.log('#4: ' + mammal.name);

The execution of this code logs:

#1: John

#2: undefined

#3: function toString() { [native code] }

#4: animal

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Why #1: John is logged?

John is logged because name is a global variable and global variables can't be deleted.

__match_answer_and_solution__

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Why #2: undefined is logged?

undefined is logged because we have deleted the name property of obj, properties or members of objects can be deleted excluding the properties or members of the global object.

__match_answer_and_solution__

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Why #3: function toString() { [native code] } is logged?

function toString() { [native code] } is logged because toString is an inherited method from Object and inherited methods or members can't be deleted.

__match_answer_and_solution__

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Why #4: animal is logged?

animal is logged because we have deleted the own mammal.name property but the inherited property is shown.

__match_answer_and_solution__

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