FE Test

01_closure.js

(function() {
  console.log(abc);
  
  var abc = "abc";
  
  console.log(myFunc());
  
  function myFunc() {
    var def = abc + 'def';
    
    return def;
  }
})();

02_loop_01.js

function loop() {
  for (var i = 0; i < 5; i++) {
    setTimeout(function() {
      console.log(i);
    }, i * 1000);
  }
}

loop();

02_loop_02.js

var assert = require('chai').assert;

var greetings = (function createMessages() {
  var messages = [];
  
  for (var i = 0; i < 10; i++) {
    messages.push(function () {
      return `Hi! I am ${i}`;
    });
  }
  
  return messages;
})();

// Let's try
try {
    assert.equal(greetings[0](), 'Hi! I am 0');
    assert.equal(greetings[7](), 'Hi! I am 7');
    
    console.info('OK');
} catch (e) {
    console.warn(e.message);
}

03_stack.js

(function() {
    console.log(1); 
    
    setTimeout(function() {
      console.log(2);
    }, 1000);
    
    setTimeout(function() {
      console.log(3);
    }, 0); 
    
    console.log(4);
})();

04_array_intersection.js

// const intersection = () => {};

const firstInput = [9, 2, 3, 5, 8, 9];
const secondInput = [3, 5, 7];

const output = intersection(firstInput, secondInput);

const output = [3, 5];

04_arrays.js

// Array.prototype.map
const persons = [
  {
    id: 1,
    name: "John Smith",
  },
  {
    id: 2,
    name: "Sam Nilson",
  }
];

function transformPersons(persons) {
  ...
}

console.log(transformPersons(persons));

// [{
//   id: 1,
//   firstName: "John",
//   lastName: "Smith"
// }, ...]

04_arrays_filter.js

const assert = require('chai').assert;

function getOddNumbers(numbers) { // odd numbers
  return [];
}

// Let's try
try {
  assert.deepEqual(getOddNumbers([ 1, 2, 3, 4 ]), [ 1, 3 ]);
  assert.deepEqual(getOddNumbers([ 2, 4, 6, 8 ]), []);
  assert.deepEqual(getOddNumbers([ 4, 6, 7, 13 ]), [ 7, 13 ]);
  
  console.info('OK');
} catch (e) {
  console.warn(e.message);
}

05_context.js

function func() {
  this.name = "John";
}

const a = func(); // a? this?
const b = new func(); // b? this?

const c = {
  name: "Sam", // do not modify
  sayName: function () {
    console.log(this.name);
  }
}

const d = ...;

d(); // => "John"