Javascript ninja secrets

ninja_secrets

It’s all about javascript cool tips and tricks which help day to day programming and reduce the time of the developer. For more tricks you can also read Tips and Tricks.

Javascript ninja secrets part - 1

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 convert value into boolean form

10. toFixed is awesome


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

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About the Author: Pankaj Bisht