JavaScript Tips and Tricks

It’s all about javascript cool tips and tricks which help day-to-day programming and reduce the time of the developer.

1. Use == instead of ===

== only check Equality and === check Equality as well as type.


[1] === 1    // is false
[1]  == 1    // is true
'1' == 1     // is true
'1' === 1    // is false
 [] == 0     // is true
 [] === 0     // is false
 '' == false   // is true but true == "a" is false
 '' === false // is false 

2. undefined, null, 0, false, NaN, ” (empty string) are all falsy.

3. Empty an array


var arr = [1, 2, 3];  
arr.length = 0; // arr will be equal to [].

Read more: Javascript array

4. while loop power


var no = 4;
while (no--) console.log(no); // 3 2 1 0

Read more: Javascript loop

5. Iterate object in forEach


var obj = { name: "xyz", age: 23 };

[obj].forEach((val)=>{
	console.log(val); //{ name: "xyz", age: 23 }
});

Read more: Javascript loop

6. Power of join


var arr = ['one', 'two', 'three'];
var list = '<ul><li>' + arr.join('</li><li>') + '</li></ul>';

console.log(list);
//<ul><li>one</li><li>two</li><li>three</li></ul>

Read more: Javascript array

7. Create object clone


var obj = { 'name': 'xyz' };
var clone = Object.assign({}, obj);
clone.age = 23;
console.log(obj); // { 'name': 'xyz' };

8. Power of logical and/or


var bol = false;
bol || console.log(bol); // false

var bol = true;
bol && console.log(bol); // true

9. Power of Double negation


var no = 2;
console.log(no); // 2
console.log(!no); // false
console.log(!!no); // true boolean conversion of no value

// it’s just converting the value into the boolean form

10. toFixed is awesome


var no = 2.44567890;
no = no.toFixed(2);
console.log(no); // 2.45

About the Author: Pankaj Bisht