Object keys and values in Javascript - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to get all keys from the object.

Javascript

const obj = {a: 1, b: 2, c: 3};
const keys = Object.[1](obj);
console.log(keys);

Drag options to blanks, or click blank then click option'

Akeys

BgetKeys

Centries

Dvalues

Attempts:

3 left

💡 Hint

Common Mistakes

Using Object.values instead of Object.keys

Trying to call a non-existent method like Object.getKeys

Object.keys(obj) returns an array of the object's own property names (keys).

2fill in blank

medium

Complete the code to get all values from the object.

Javascript

const obj = {x: 10, y: 20, z: 30};
const vals = Object.[1](obj);
console.log(vals);

Drag options to blanks, or click blank then click option'

Avalues

Bkeys

Centries

DgetValues

Attempts:

3 left

💡 Hint

Common Mistakes

Using Object.keys instead of Object.values

Trying to call a non-existent method like Object.getValues

Object.values(obj) returns an array of the object's own property values.

3fill in blank

hard

Fix the error in the code to get entries from the object.

Javascript

const obj = {name: 'Alice', age: 25};
const entries = Object.[1](obj);
console.log(entries);

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Akeys

Bvalues

Centries

DgetEntries

Attempts:

3 left

💡 Hint

Common Mistakes

Using Object.getEntries which does not exist

Using Object.keys or Object.values instead of Object.entries

Object.entries(obj) returns an array of [key, value] pairs from the object.

4fill in blank

hard

Fill both blanks to create an object from entries and get its keys.

Javascript

const entries = [['a', 1], ['b', 2]];
const obj = Object.[1](entries);
const keys = Object.[2](obj);
console.log(keys);

Drag options to blanks, or click blank then click option'

AfromEntries

Bvalues

Ckeys

Dentries

Attempts:

3 left

💡 Hint

Common Mistakes

Using Object.entries instead of Object.fromEntries

Using Object.values instead of Object.keys to get keys

Object.fromEntries creates an object from key-value pairs. Object.keys gets the keys of that object.

5fill in blank

hard

Fill all three blanks to filter object keys with values greater than 10.

Javascript

const data = {a: 5, b: 15, c: 25};
const filteredKeys = Object.[1](data)
  .filter(key => data[key] [2] 10)
  .map(key => key.[3]());
console.log(filteredKeys);

Drag options to blanks, or click blank then click option'

Akeys

B>

CtoUpperCase

Dvalues

Attempts:

3 left

💡 Hint

Common Mistakes

Using Object.values instead of Object.keys to get keys

Using '<' instead of '>' in filter condition

Using toLowerCase instead of toUpperCase

Object.keys gets keys, filter selects keys with values > 10, map converts keys to uppercase.