Make Advanced your JavaScript Superpower-

Let’s talk about some advanced JavaScript methods.

True and False:

//False:
// false
// 0
// “”
// udenfined
// null
// NaN
//True: 
// ’0'
// ‘ ‘ 
// [] 
let name = 12;
if(name || name == 0){ 
console.log(“condition is true”);
}
else{
 console.log(“condition is false”);
}

Null VS Undefine:

let num;
function add(num1, num2){ 
console.log(num1 + num2); 
return 
} 
function add(num1, num2){
 console.log(num1, num2);
} 
const student= {name:”smart dude”, phone:458421};
console.log(student.id); 
let fun = undefined;
console.log(fun); 
let ages = [2, 5, 9]
console.log(ages[11]);

Duble VS Tripple Equal:

const first = 0;
const second = false;
if(first == second){
 console.log(“condition is true”);
}
else{
 console.log(“condition is false”);
}
const first = 0;
const second = false;
if(first === second){
    console.log("condition is true");
}
else{
    console.log("condition is false");
}

Map and Filter:

const numbers = [3, 4, 5, 6, 7, 8];
// const output = [];
// for(let i = 0; i < numbers.length; i++){
// const element = numbers[i];
// const result = element * element;
// output.push(result);
// }
// function square (element){
// return element * element;
// }
// const square = element => element * element;
// const square = x => x * x;
// const result = numbers.map(function(element){
// return element * element;
// })
// const result = numbers.map(x => x * x);
// console.log(result);
const bigger = numbers.filter( x => x < 3);
const isThere = numbers.find(x => x > 5);
console.log(isThere);

Apply Map and Filter:

const students = [
 {id: 21, name: ‘Sunny’},
 {id: 31, name: ‘Munna’},
 {id: 41, name: ‘Mamun’},
 {id: 71, name: ‘Dilruba’}
];
const names = students.map( s => s.name);
const ids = students.map(s => s.id);
const bigger = students.filter( s => s.id>40);
const biggerOne = students.find( s => s.id>40);
console.log(biggerOne);

Scope:

let bonus = 20;
function sum(first, second){
 let result = first + second + bonus;
 //console.log(bonus);
 if(result > 9){
 var mood = “happy”;
 mood = “fishy”;
 mood = ‘funky’;
 mood = “cranky”
 //console.log(mood);
 }
 console.log(day);
 let day = “friday”;
 
 return result;
}
const output = sum(3, 7);
//console.log(bonus);
//console.log(output);

Closure:

function stopWatch(){
 let count = 0;
 return function(){
 count++;
 return count;
 }
}
const clock1 = stopWatch();
console.log(clock1());
console.log(clock1());
console.log(clock1());
console.log(clock1());
const clock2 = stopWatch();
console.log(clock2());
console.log(clock2());
console.log(clock1());
console.log(clock2());

Array Split:

const nums = [1,2,3,4,5,6,7,8];
//const part = nums.slice(2, 5);
const removed = nums.splice(2,3, 77);
// console.log(removed);
// console.log(nums);
const together = nums.join(“ami”)
console.log(together);

Break and Continue:

const nums = [1,-2,3,4,-5,-6,7,-8,9];
for(let i = 0; i < nums.length; i++){
 
 if(nums[i]>3){
 break;
 }
 //console.log(nums[i]);
}
for(let i = 0; i < nums.length; i++){
 if(nums[i]<0){
 continue;
 }
 console.log(nums[i]);
}