Destructuring

https://www.youtube.com/watch?v=s5QZIhooG0U

let obj = {
    name: 'John',
    interests: ['reading', 'running', 'javascript'],
    email: 'jtlim0414@gmail.com'
}

console.log(obj.name)

https://www.youtube.com/watch?v=NIq3qLaHCIs

const personOne= {
    name: 'Kyle',
    age: 24,
    address: {
        city: 'Somewhere',
        states: 'One of them'
    }
}

const personTwo = {
    name: 'Sally',
    age: 32,
    address: {
        ciry: 'Somewhere else',
        states: 'Another one of them'
    }
}

QUEUE

https://st-lab.tistory.com/183

https://www.youtube.com/watch?v=A3ZUpyrnCbM

https://www.youtube.com/watch?v=bK7I79hcm08

function Queue {

    collection = [];
    this.print = function () {
        console.log(collection);
    }

    this.enqueue = function(element) {
        collection.push(element)
    };

    this.dequeue = function() {
        return collection.shift();
    }

    this.front = function() {
        return collection[0]
    }

    this.size = function() {
        return collection.length
    }
    this.isEmpty = function() {
        return (colletion.length ===0);
    };
}

var Queue = function () {
  this.head = 0;
  this.tail = 0;
  this._storage = {};
};

Queue.prototype.add = function (val) {
  this._storage[this.head] = val;
  this.head++;
};

Queue.prototype.remove = function () {
  if (this.head === this.tail) {
    return undefined;
  }
  let removedElement = this._storage[this.tail];
  delete this._storage[this.tail];
  this.tail++;
  return removedElement;
};

https://www.youtube.com/watch?v=lccLGGaOMi4

https://www.youtube.com/watch?v=okr-XE8yTO8

아 this.head 랑 this.tail이 index 역할을 하는거다.

Inheritance Class

class Person {
  constructor(name, age) {
    this.name = name;
    this.age = age;
  }

  get profile() {
    return `Name: ${this.name}, Age: ${this.age}`;
  }

  introduce() {
    return `Hello, my name is ${this.name}`;
  }
}

var person = new Person("James", 90);

console.log(person.profile);
console.log(person.introduce());

class Developer extends Person {
  constructor(name, age) {
    super(name, age);
  }

  work() {
      return 'doing javascript';
  }
}

var developer = new Developer("John", 80);

console.log(developer.introduce());

https://www.youtube.com/watch?v=_DLhUBWsRtw

https://medium.com/@chinup.peter/prototypal-inheritance-in-javascript-the-big-picture-1fb20b63b210

Recurssion Array

https://medium.com/@daniel.oliver.king/getting-started-with-recursion-f89f57c5b60e

Most of the time, I have heard people teaching recursion focus far too much on the base case, and not enough on the recursive case. People usually don’t have much trouble realizing what the base case should be — the harder part is deciding how the recursive call should be structured in order to accomplish the computation you want. Unfortunately, it is difficult to find useful advice about how we should go about doing this. This is what I would like to talk about here — how we should think when writing a recursive algorithm.

https://www.youtube.com/watch?v=0wf14oAZPo8

function flatten (array) {
    ///create a brand new array
    let arr=[];
    // write a for loop
    for(let i =0; i<array.length;i++) {
        let element = array[i];
        // if the element is an array, recurse
        if (Array.isArray(element)) {
            flatten(element);
        } else {
            // else, push the single value into the new array
            arr.push(element);
        }
    }
    return arr;
}

flatten([1,2,[3,4,[5]]]);

function flatten (array) {
  /// create a blank array
  let arr =[];
  /// create a helper function with array argument
  function helper  (array) {
  /// wirte a for loop
    for(let i=0; i< array.length; i++) {
      let element = array[i];
      /// if the element is an array, recurse with helper function
      if(Array.isArray(element)) {
        helper(element);
      } else {
        arr.push(element)
      }
      /// else, push the element into the balnk array
    }
  }
  /// call helper function
  helper(array);
  /// return the array
  return arr;
}
flatten([1,2,[3,4,[5]]]);

const printArray = function (arr) {
  if (arr.length === 0) {
    return;
  }
  arr.forEach(el => {
    if (Array.isArray(el) === true) {
      printArray(el);
    } else {
      console.log(el);
    }
  });
};