Difference between object literal and constructor function.
1. Object Literal
An object literal is the simplest way to create an object in JavaScript.
You directly define the object and its properties in curly braces {}.
// Object Literal
const person = {
name: "John",
age: 25,
greet: function () {
console.log("Hello, my name is " + this.name);
}
};
person.greet(); // Hello, my name is John
🔹 Key Points:
- Quick and easy to create.
- All properties and methods are defined inline.
- Creates a single object instance.
- No reusable “template” for multiple objects.
2. Constructor Function
A constructor function is a special function used to create multiple objects of the same “type.”
By convention, the function name starts with a capital letter.
// Constructor Function
function Person(name, age) {
this.name = name;
this.age = age;
this.greet = function () {
console.log("Hello, my name is " + this.name);
};
}
const person1 = new Person("Alice", 30);
const person2 = new Person("Bob", 40);
person1.greet(); // Hello, my name is Alice
person2.greet(); // Hello, my name is Bob
🔹 Key Points:
- Used with the
newkeyword. - Each call creates a new object instance.
- Makes it easy to create multiple similar objects.
- Common behavior can be moved to
Person.prototypeto save memory.
Main Differences
| Feature | Object Literal | Constructor Function |
|---|---|---|
| Creation | Defined directly with {} | Defined with a function + new |
| Reusability | Not reusable (creates one object only) | Can create multiple objects |
| Syntax | Simple and short | More verbose |
| Use Case | Single, simple objects | Multiple objects of same type (blueprint) |
✅ Summary:
- Use object literals for one-off objects.
- Use constructor functions (or modern
class) when you need a reusable blueprint for creating many similar objects.
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