5 a simple test for job position Junior Frontend developer

Tells Daria Pushkarskaya — founder and owner of online schools in the IT-sphere Web Hero School

The statistics of our students, every fifth interview for the position Junior Frontend developer — successful. A big role in the final decision on the candidate plays the test task and the questions. This is one of the stages of selection, and if you came to him — congratulations, it is a great achievement! Now you need to show what you have learned to take a desired position.

Below are examples of the tasks faced by our students for interviews and gives some suggestions on how to cope with them. To predict the exact wording of your test is impossible, but we have formed a General idea about the level of difficulty and the types of tasks that you have to solve.

1. That displays the following code?

function b(x, y, a) { arguments[2] = 10; alert(a); } b(1, 2, 3); Answer & explanation

Answer: 10

Explanation: In the function b 3 argument indexes start from [0]. Thus, the argument with index [2] is a. The first line of the function the third argument of the function is assigned the value 10.

2. What displays in the console the following code?

console.log(false == undefined); console.log(false == null); console.log(null == undefined); Answer and explanation

Answer: false false true

Description: == compares for equality, and does not check identity of types, so the third line of code in the console will output the value true.

3. What displays in the console the following code?

const numbers = [1, 2, 3, 4, 5]; const [y] = numbers; console.log(y); the Answer and explanation

Answer: 1

Explanation: In this example, the destructurization is performed. Default y variable is assigned the value of the first element of the array.

4. The order in which scripts are executed? Why?

<script async src="script-1.js"></script> // load Time of 1.5 s the script <script src="script-2.js"></script> // load Time of the script 1s <script defer src="script-3.js"></script> // load Time of the script 3s <script defer src="script-4.js"></script> // load Time of 1.5 s the script <script src="script-5.js"></script> // load Time of the script 2s <script async src="script-6.js"></script> // load Time of the script 1s <script defer src="script-7.js"></script> // load Time of the script is 0.1 s Response and explanation

Answer:

1. <script src="script-2.js"></script> // load Time of the script 1s
2. <script async src="script-6.js"></script> // load Time of the script 1s
3. <script async src="script-1.js"></script> // load Time of the script 1.5 s
4. <script src="script-5.js"></script> // load Time of the script 2s
5. <script defer src="script-3.js"></script> // load Time of the script 3s
6. <script defer src="script-4.js"></script> // load Time of the script 1.5 s
7. <script defer src="script-7.js"></script> // load Time of the script is 0.1 s

Explanation: When the browser loads the HTML and reaches the <script>tag...</script> he can't continue to build the DOM. He must first execute the script. The same thing happens with external scripts <script src="..."></script>: the browser should wait until the boot script, execute it and only then process the rest of the page.

async: load Order (who will be loaded first, and work). Can run before page is fully loaded. This happens if the scripts are small or are stored in the cache, and the document is quite large.

defer: the Order of the document (located in the document). Runs after the document is loaded and processed (waiting for) just before DOMContentLoaded.

Therefore, we first executed the script 1 because it is first in the queue and the speed of download. 2 because he is my upload speed fast is 1 second. Download, async — queue, 3 script loaded in 1.5 seconds and boot, then 4 the script loaded in the queue and the speed of 2 seconds, the last scripts 5, 6, 7. They are loaded at the end and in turn embed in the DOM.

5. What displays in the console this code?

let x = 3; function fn() { x = 10; return; function x() {} } fn(); console.log(x); the Answer and explanation

Answer: 3

Explanation: x is declared as a function, so in the end she periapicals from 10 to 3.

Remember that each interview is a unique chance to receive feedback from experienced experts, use it for your development. Always ask for feedback on the test task, so that it became the point of your growth. As an experienced programmer and the owner of online-school web developers can also provide the following tips for a successful interview:

1. The employer understands that you don't know just because you are middle or senior developer. You will not require a high level of code execution, but that is no reason to relax.
2. The correct reference solution of the problem does not exist. If you don't know how to cope with test — make a few assumptions and show your train of thought.
3. Programming is the development of practical skills, so solve as many tasks in order to develop a skill profile of thinking.
4. The applicant admits that you don't know the solution, and that such situations will occur in the work. Therefore, it is important to show your thinking when you don't know the answers. Vocalize or write to assumptions, describe attempts, demonstrate their readiness for such challenges.
5. One of the key qualities of a Junior — to be able to ask questions to deal with feedback and learn quickly. Show your willingness to develop and proactivity through the questions. When you took the job, ask for feedback on it. Ask, what to expect from you, how your solution is optimal. This will distinguish you from other candidates.

Remember that the position of the young specialist in great demand, and you need to stand out among competitors. The company is ready to invest in you and train, but you must be active, ask questions, show your ability to learn and interest in the position. Remember that many companies primarily looking for is fire in the eyes, desire to grow and develop.

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