Q
How can you iterate over all properties of an object?

Answer & Solution

Answer: Option B
Solution:
The for...in loop iterates over all enumerable properties of an object.
Related Questions on Average

What does Object.keys(obj) return?

A). An array of the values of the object's properties

B). An array of the names of the object's properties

C). The first key of the object

D). The number of properties in the object

How do you define a constructor function for a Car object?

A). function Car(make, model, year) { this.make = make; this.model = model; this.year = year; }

B). Car(make, model, year) { this.make = make; this.model = model; this.year = year; }

C). function create Car(make, model, year) { this.make = make; this.model = model; this.year = year; }

D). function construct Car(make, model, year) { this.make = make; this.model = model; this.year = year; }

What will the following code output? console.log(car.make); if var car = {make: 'Honda', model: 'Civic'};

A). Honda

B). Civic

C). Undefined

D). Error

In JavaScript, what keyword is used to define a new object from a constructor function?

A). create

B). construct

C). new

D). object

How do you add a new property to an existing object in JavaScript?

A). object.property = value;

B). object->property = value;

C). object:property = value;

D). object.addProperty('property', value);

How do you create a method inside an object using an object literal?

A). methodName: function() {}

B). methodName = function() {}

C). methodName: () {}

D). methodName: method() {}

What is the purpose of the this keyword in an object method?

A). It refers to the global object.

B). It refers to the current object.

C). It refers to the parent object.

D). It refers to the previous object.

Which method can be used to call a function defined within an object?

A). object.functionName();

B). object->functionName();

C). object::functionName();

D). object.callFunction('functionName');

What is the output of car.start() if var car = {start: function() {console.log('Car started');}};?

A). Car

B). started

C). Car started

D). Error

What will car['make'] return if var car = {make: 'Ford', model: 'Mustang'};?

A). Ford

B). Mustang

C). Undefined

D). Error