Q
How can you check if the age property exists in the person object?

Answer & Solution

Answer: Option D
Solution:
person.hasOwnProperty('age') checks if age is a direct property of person.
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How do you iterate over all properties of an object var person = {name: 'John', age: 30};?

A). for (var key in person)

B). for (var key of person)

C). forEach(key in person)

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A). class ClassName { constructor() {} }

B). function ClassName() { constructor() {} }

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A). var myCar = new Car('Toyota', 'Corolla');

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A). methodName() {}

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How do you define a method named greet in an object var person = {};?

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A). var obj = {};

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What will the following code output? console.log(person['age']); if var person = {name: 'John'};

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D). null