Overview

Welcome to Node.js assessment.

You are required to pass the test to prove your skills; the test consists of:

• Part1: Javascript/Typescript Test
• Part2: Node.js Test

Initialize the Project

To start your assessment, clone the project into a local machine. This project runs on Node.js LTS.

Initialize the project by running

npm install

To start the installation of the project dependencies to the local machine.

now...

The typescript files you need to work on are in src directory. You can compile them by running

npm run build

You can have it automatically compile while you edit the files by running

npm run watch-ts

You're all set now!

Assessment Submission

After finishing your assessment, the candidate must do the following:

1. Delete the node_modules and dist folders.
2. Compress all the remaining files in this folder into any compressed format (.zip, .rar, .tar, .gz, or any).
3. Send the file back to us via Email.

Please note that, editing any of the irrelevant files (Outside of src/part1 and src/part2) may affect your assessment result.

Part 1

Javascript/Typescrypt skill. This part focuses on language syntax and skills. The assessments also involve basic Programming and Logical thinking.

Prerequisites

This part's materials are in src/part1. Each of the questions is separated in its file with a corresponding name. For answering each question, please write them in the provided function contained in each file.

You are free to install any library you require. This project initially comes with lodash installed

The project is initialized with the latest ES2017 syntax. The syntax list that is set up and available to use are:

• const, let
• () => {} arrow function
• Promise
• async/await
• ES6 class
• ...obj spread operator

Evaluation

The evaluation can execute through:

npm run test-part1

If the result shows to be 100%, you are more likely to do it right!

1. Asynchronous Delay

One of your program parts needs to wait for I/O function call. Write a function that can delay the process in Javascript. The function should take the first argument as delay which is the delay time in millisecond. Also, the second argument, callback which is the continuing process that should run after the delay millisecond had passed.

For example, your function

asynchronousDelay(3000, () => {
  console.log("haha")
})

should log out haha after 3 seconds.

2. Transform Arguments!

Assuming you have a function which takes a large number of arguments. For example, sum(a, b, c, d, e, f) takes 6 arguments and return a summation of each argument. Write a function transformArgumentsToArray that take a function similar to sum as its argument, and return a new function. This new function takes only 1 argument as an array, but still be able to process exactly as the function pass to transformArgumentsToArray.

For example, if we pass sum function to transformArgumentsToArray, it will return a new function that can take newSum([a, b, c, d, e, f]) and will still return the same result as calling sum(a, b, c, d, e, f).

// for example
sum(1, 2, 3, 4, 5)
// -> return 15

// passing sum to the function will return newSum function
const newSum = transformArgumentsToArray(sum)
// calling newSum with array param
newSum([1, 2, 3, 4, 5])
// -> return 15

3. 24K Magic in the Array

Have the function magicArray(arr) take the arr array and return the summation of each member in the array under these conditions:

• member of arr is guaranteed to be Number type.
• If any member in arr is divisible by 7, it is excluded from the calculation. For example, if the array is [5, 3, 14, 8] the number 14 is ignored.
• The function should return the summation of the other member in the array.
• For example, [5, 3, 14, 8] should return 16.

4. Wait a minute

Have the function waitAMinute(startTime, endTime) take two number of arguments. These arguments are the start time and end time in timestamp in standard timestamp in string format: 2018-06-01T08:18:12.907Z. This function counts the interval called "Pomodoro" which is the focus working time interval that goes like this; Work 25 minutes then break a short break for 5 minutes. Then, back to work for 25 minutes and so on. The timer goes on for 4 intervals, after the 4th work interval, the break interval would be a long break which take 15 minutes. After that, it would be a work time again for 25 minutes. So the whole thing starts over.

For example, the interval went on like this;

Start: Pomodoro 1

==== 25 minutes passed ====

break 1 (Short break)

==== 5 minutes passed ====

Start pomo 2

==== 25 minutes passed ====

break 2

==== 5 minutes passed ====

Start pomo 3

==== 25 minutes passed ====

break 3

==== 5 minutes passed ====

Start pomo 4

==== 25 minutes passed ====

break 4 (Long Break)

==== 15 minutes passed ====

Start pomo 5

=== another 25 minutes ====

... and so on

This function waitAMinute(startTime, endTime) count and return the number of Pomodoros completed during startTime and endTime, note that an incomplete Pomodoro must be discarded.

For example:

waitAMinute("2018-06-01T08:18:12.907Z", "2018-06-01T09:08:12.907Z")
// -> return 1

waitAMinute("2018-06-01T08:18:12.907Z", "2018-06-01T09:14:12.907Z")
// -> return 2

waitAMinute("2018-06-01T08:40:39.024Z", "2018-06-01T11:21:54.099Z")
// -> return 5

Note:

• It's guaranteed that endTime is always be later than startTime
• You are free to use any library you wish. Though, you need to install it right :D.

Part 2

Backend skill. This part will focus on Node.js common widely use libraries and how to implement them.

Prerequisites

This part's materials are in src/part2. This part contains an ecosystem project built base on the Node.js popular web server, Express.js. Your task would be to write API(s) for each of the assessments, most of the setup had been prepared fairly well. Be sure to understand the setup and write your assessment from the setup. Further instruction will be given upon each assessment.

Evaluation

The project is set up with Express.js, and it can run via

npm run start-part2

The Web server will start through port 3000, and you are good to go.

Same as part1, the evaluation can execute through

npm run test-part2

1. A bunch of readmes

In the folder files/readme contains several text files with a specific name, write an API with the spec.

GET /files/:filename

The filename should be the file name in the files/readme folder on which the API should read.

The response should return file name, string character count, and the content of the file in JSON format like this:

{
  "filename": "the-file-name",
  "length": "as string character count of the file",
  "content": "...the content of the file"
}

for example,

GET /files/hello-world.txt

should return

{
  "filename": "hello-world.txt",
  "length": 12,
  "content": "hello world!"
}

In case the file name does not exist in the folder, the API should return with http status code 404 with this error.

{
  "error": "file not found!",
  "code": 404
}

2. A RESTful way

In the src/part2/routes/users.js, there is an unfinished Restful API that needs to be improved! Currently, the users API returns a set of user data persisting in our database.

A. Enhance user list

The API get users list is the following:

GET /users

At the moment, the API only return dump user object.

[
  {
      "_id": "the-id",
      "isActive": true,
      "firstName": "Some-one",
      "lastName": "Good-name",
      "balance": "₹2000"
  }
]

Ideally, this API should return the list of users contains in the database as an array list.

For the sake of this assessment, we provide a function which virtually gets users from the persistent storage. The getUsers() function read database with delay time about 300-800 millisecond. Therefore, it returns a Promise that resolve the array of all Users.

[
  {
    "_id": "5dbf0b6cb54f57e25f28b7d7",
    "isActive": false,
    "firstName": "Gonzalez",
    "lastName": "Spence",
    "balance": "₹10,501.04",
    "age": 37,
    "eyeColor": "blue",
    "company": "QIAO",
    "email": "gonzalez.spence@qiao.org",
    "phone": "+91 8824602720",
    "address": "305 Cass Place, Lodoga, Idaho, 2921",
    "registered": "Sunday, December 10, 2017 5:40 AM"
  },
  {
    "_id": "5dbf0b6cf24edbfa1662df9a",
    "isActive": false,
    "firstName": "Oneal",
    "lastName": "Prince",
    "balance": "₹19,874.09",
    "age": 34,
    "eyeColor": "brown",
    "company": "HAIRPORT",
    "email": "oneal.prince@hairport.io",
    "phone": "+91 9555372987",
    "address": "405 Jackson Street, Lowell, North Carolina, 5385",
    "registered": "Tuesday, December 13, 2016 9:04 PM"
  },
  {
    "_id": "5dbf0b6c98900a329ab71351",
    "isActive": false,
    "firstName": "Poole",
    "lastName": "Duran",
    "balance": "₹19,747.36",
    "age": 34,
    "eyeColor": "blue",
    "company": "INDEXIA",
    "email": "poole.duran@indexia.ca",
    "phone": "+91 8134723840",
    "address": "522 Oliver Street, Chicopee, Puerto Rico, 8120",
    "registered": "Friday, November 14, 2014 6:32 AM"
  },
  ...
]

However, for this API endpoint, we do not want all the detail object to return with this API. The API we actually want should look like this:

// GET /users
// will return
[
  {
    "_id": "5dbf0b6cb54f57e25f28b7d7",
    "isActive": false,
    "firstName": "Gonzalez",
    "lastName": "Spence",
    "balance": "₹10,501.04"
  },
  {
    "_id": "5dbf0b6cf24edbfa1662df9a",
    "isActive": false,
    "firstName": "Oneal",
    "lastName": "Prince",
    "balance": "₹19,874.09"
  },
  {
    "_id": "5dbf0b6c98900a329ab71351",
    "isActive": false,
    "firstName": "Poole",
    "lastName": "Duran",
    "balance": "₹19,747.36"
  },
  ...
]

Write this API to return data from users accordingly.

B. Get only one user!

Now, the data that we hide for each user should be exposed to the consumer. However, this time, instead of returning all user, we will allow the API caller to call a URL and get only one User (resource).

Write a new API that follows RESTful convention. This API should return a single user object which matches _id param specify in the API endpoint.

Note: For this API, you do not need to hide any user information, since we return only 1 user, we need to expose as many details as possible!