Why NOT to Use var and Instead Use let or const in JavaScript

Consider the following example code:


You can note that the value of var a has changed due to the assignment within the block scope of the if statement, while the value of let b & const c value have remained unaffected.

So, the way let & const works is the way most programming languages work.

var is kind of weird, it’s one of the things a lot of people didn’t like about JavaScript. It causes security risk and confusion and hence it’s better to avoid it.

JavaScript Equivalent of PHP's number_format() Function

Today while going through JavaScript I came across a float value and then wanted to truncate it by two decimal places. I knew in PHP we have the number_format() function and this is what I found for Javascript:

yourFloatVarHere.toFixed(2);

Example:

Suppose you have a value say: 0.589723, and you would like to truncate this value to two decimal place.

 var divide;  
 var num_format;  
 divide = 33/86;  
 num_format = divide.toFixed(2);  

33/ 8 = 0.38372093
Since we have truncated our answer to two decimal place, the final answer will be: 0.38