This RxJS Online Test
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About the test

The RxJS online test evaluates the candidates knowledge of key concepts for reactive programming with RxJS and the various prebuilt operators that come with the library.

It is an ideal test for pre-employment screening. A good RxJS developer should be able to work with the library to write asynchronous and event-based programs and know how and when to use prebuilt operators.

The online test requires candidates to answer multiple choice and fill-in-the-blank questions about RxJS.

Sample public questions

3 min
Creation Operator
Pipeable Operator
RxJS Observable

An online streaming platform uses the following RxJS code to log the number of seconds passed in a video:

const seconds = interval(1000).pipe(
  map((x) => x + 1),

const logger = seconds.subscribe((x) =>
  console.log(`Seconds passed: ${x}`)

setTimeout(() => {
}, 5000);

What options will be true about seconds and logger after the code above is executed?

5 min
RxJS Subject

Consider the following RxJS code for pushing and logging weather data:

const weatherSubject = new _______________({temperature: 0 , rainChance: 0});
const sendWeatherData = (weatherData) => {

sendWeatherData({temperature: 35.5 , rainChance: 20});
sendWeatherData({temperature: 34 , rainChance: 25});

weatherSubject.subscribe((x) => {
  console.log("Current Temperature: " +  x.temperature);

sendWeatherData({temperature: 28 , rainChance: 50});

weatherSubject.subscribe((x) => {
  console.log("Chance of rain: " + x.rainChance);

sendWeatherData({temperature: 25 , rainChance: 90});

Fill in the blanks above so that the following output is produced after running it:

Current Temperature: 34
Current Temperature: 28
Chance of rain: 50
Current Temperature: 25
Chance of rain: 90

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Skills and topics tested

  • RxJS
  • Creation Operator
  • Pipeable Operator
  • RxJS Observable
  • Bug Fixing
  • RxJS Subject

For job roles

  • RxJS Developer

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