Top ten Javascript tricks part 3

Different ways to pass parameters to a setTimeout

const addNum = (a, b) => console.log(a + b); setTimeout(addNum, 1000, 2, 3) //result: 5 setTimeout(() => { addNum(2,3); },1000) //result: 5 setTimeout(addNum.bind(null, 2, 3), 1000); //result: 5

3 ways to get the Date and Time in milliseconds

new Date().getTime(); // 1576509862158 Date.now(); // 1576509862158 +new Date(); // 1576509862158

function() declaration in ES5 and ES6

// old way ES5
function tomAndJerry(){
}

// Es6
tomAndJerry() => {
}

Caching the array.length in the loop

let array = new Array(le9);

for(let i = 0; i < array.length; i++){
// this loop will calculate array length in each iteration
}

for(let i = 0; length =  array.length; i < array.length; i++){
// this loop will calculate array length only once
}

Different approaches to creating an HTML link

let myText = 'Click me please'

// usual way
`<a href="#">${myText}</a>`
// <a href="#">Click me please</a>

// Using link method
myText.link(#);
// <a href="#">Click me please</a>

Easily check the visibility of div or page

window.addEventListener('visiblitychange', ()=> {
// document => define any html element div, a, span
if(document.hidden){ 
console.log('div is hidden')
}else{
console.log('div is visible')
}
})

Check the data array or not? using isArray()

let array = [1,2,3,4]
let numb = 3

Array.isArray(array) // return true

Array.isArray(numb) // return false

Array.reduce()
It applies a function to each element in an array and reduces the array into a single element.

const arr = [5, 10, 15, 20, 25];

const result  = arr.reduce((total, currentValue) => {
console.log(currentValue); // 5 10 15 20 25
return total+currentValue;
});

console.log(result)
//result 75

How to verify that a given argument is a number

isNumber = (n) => {
return !isNaN(parseFloat(n)) isFinite(n);
}

isNumber(4) // true

isNumber(4.4) // true

isNumber('4') // false

Generate a random set of alphanumeric characters

// genreate random aplhanumeric
generateRandomAlphaNum = len =>{
var rdmString='';
for(; rdmString.length < len; rdmString += Math.random().toString(36).substr(2));
return rdmString.Substr(0, len);
}


generateRandomAlphaNum(5) // result blphj
generateRandomAlphaNum(11) // result: uug4th6ie2h
generateRandomAlphaNum(8) // result: rimbe38x

I hope this will help your developing skills. If any queries feel free in below comment section. Have a great day!.

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