EBS FE Test 1

Requirements:

1. Typescript
2. TS Compiler
3. ESLint + Prettier

Getting started:

1. Clone the repository
2. Run yarn to install necessary dependencies.
3. Run yarn build to compile your code.
4. Run yarn start to run your code and see the result on terminal.

Todo:

(scroll down to see more information about every task)

1. Create reduce function
2. Create find function
3. Create concat function
4. Create pipe function

All the functions should not use regular Array.prototype.reduce(), Array.prototype.concat() or Array.prototype.find(), they should be realized using only for(), while() and etc ..

reduce(arr, (stop) => (acc, current, index) => {}, initialValue)

• It should have functionality to stop cycle using stop function

const arr = ['spray', 'limit', 'elite', 'exuberant', 'destruction', 'present'];

const obj = reduce(
  arr,
  (stop) => (acc, current, index) => {
    if (index === 3) {
      stop();
    }

    return { ...acc, [index]: current };
  },
  {}
);

console.log(obj); // Result: { 0: 'spray', 1: 'limit', 2: 'elite' }

find(arr, (item, index) => {})

const arr = [
  { id: 0, name: 'spray' },
  { id: 1, name: 'limit' },
];

console.log(find(arr, (item) => item.id === 1)); // Result: { id: 1, name: 'limit' }
console.log(find(arr, (item) => item.id === 10)); // Result: undefined

concat(arr1, arr2, arr3, ...)

• The number of arrays should be unlimited. It can be 2, 3 or even 10.

const arr1 = ['spray', 'limit', 'elite'];
const arr2 = ['exuberant', 'destruction'];
const arr3 = ['present'];

concat(arr1, arr2); // Result: ['spray', 'limit', 'elite', 'exuberant', 'destruction']
concat(arr1, arr2, arr3); // Result: ['spray', 'limit', 'elite', 'exuberant', 'destruction', 'present']

pipe(arr, [concat(), reduce(), find(), ...])

• All functions such as reduce, find & concat should not expect first argument (array) in case when they're in a pipe, it should be passed automatically.

const arr1 = ['spray', 'limit', 'elite'];
const arr2 = ['exuberant', 'destruction'];
const arr3 = ['present'];

pipe(arr1, [
  concat(arr2, arr3), // Result: ['spray', 'limit', 'elite', 'exuberant', 'destruction', 'present']
  reduce(
    (stop) => (acc, current, index) => {
      if (acc.length === 2) {
        stop();
      }

      // get only even elements
      if (index % 2 == 0) {
        acc.push({ index, label: current });
      }

      return acc;
    },
    []
  ), // Result: [{ index: 2, label: 'limit' }, { index: 4, label: 'exuberant' }]
  find((item) => item.label.length > 5), // Result { index: 4, label: 'exuberant' }
]);

// Result { index: 4, label: 'exuberant' }