const firstName = 'Vysakh'
  const lastName = 'Sreenivasan'
  const year = 2018
  const name = `${firstName} ${lastName}-${year}` 
  // use backtick whenever you want a combination of values together

  const url = 'final&extra'
  const parts = url.split('&') // => ['final', 'extra']
  // split will come handy in many scenarios

// create 
let list = ['blog', 2018, 12.2]

// read
list[0] // => blog

// update
list[0] = 'article'
list.splice(2, 0, 'extra')
// remove 0 element from index 2 and insert 'extra'

list.push(4) // pushes to the last
list.unshift(0) // pushes to the first

// delete
delete list[0]
list.splice(2, 1)
list.pop()
list.shift()

// create 
let languages = {spain: 'spanish', china: 'chinese', france: 'french'}

// read
languages.spain
languages['spain']

// update
languages['spain'] = 'someCreole'
languages.china = 'mandarin'
languages['germany'] = 'german'


// delete
delete languages['spain']

// transform all elements based on a condition
// into another array of same length
const num = [1, 2, 3]
const squares = [1, 2, 3].map((i) => i*i)

// get a subset of an array which 
// satisfies a condition
const num = [1, 2, 3]
const odd = [1, 2, 3].filter((i) => i%2 != 0)

// reduce the array into a single value
// based on some logic

const num = [1, 2, 3]
const sum = [1, 2, 3].reduce((sum, i) => sum + i, 0)
// => 6

// Tip: You'll always have some problem involving array
// transformation. 
// If the resultant array always has the
// same length as the original, go with map.
// If you have to filter or there is 
// lesser elements in the resultant array go with filter. 
// If there is one single value, go with reduce.

class Cat {
    constructor(name) {
        this.name = name;
    }
    meow() {
        console.log(this.name)
    }
}
const cat1 = new Cat("kitty")
cat1.meow() // => kitty

// this. ==> refers to instance variable.
// the instance/object variable is available to
// all the functions of the object, 
// that is the purpose of it.