How to check if a property is present in an object in JavaScript?

Published June 23, 2020

Let's say you have an object called John.

const John = {
  name: "John Doe",
  age: 23,
  salary: 23000,
};

We can check whether the property salary property is present in the object using the hasOwnProperty() method available in the prototype chain of the John object.

const John = {
  name: "John Doe",
  age: 23,
  salary: 23000,
  sayHello: () => {
    console.log("Hello!");
  },
};

// check if the salary is present in John
John.hasOwnProperty("salary");
  • The method returns true if present and false if not.
  • Available in the prototype chain of an object.

You can also check if a method is present in the object.

Now let's check if sayHello method is present.

const John = {
  name: "John Doe",
  age: 23,
  salary: 23000,
  sayHello: () => {
    console.log("Hello!");
  },
};

// check if the salary is present in John
John.hasOwnProperty("salary"); // Result: true

// check if sayHello function is present in John
John.hasOwnProperty("sayHello"); // Result: true

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