Skip to main content


Showing posts with the label reference

parseInt() galore

After the Falsy  post, here is another interesting table listing various values as evaluated by parseInt() . Some are quirky indeed :) Free lunch to anyone who shows me another table that covers parseInt() in such detail :P Expression Value Remarks parseInt("23") 23 parseInt(" 23") 23 Leading white space is dropped parseInt("-23") -23 parseInt(23) 23 parseInt(023) 19 Radix 8 is used parseInt(0x23) 35 Radix 16 is used parseInt("23",4) 11 Radix 4 is used parseInt("23",4.99) 11 Radix is always converted to int32 parseInt("23",36) 75 Radix 36 is used parseInt("z",36) 35 Radix 36 is used parseInt("23",37) NaN Max Radix is 36 parseInt("23",1) NaN Min Radix is 2 parseInt("23",0) 23 Radix used is 10 parseInt("23",-1) NaN Min Radix is 2 parseInt("23",3) 2 Radix 3 can use only 0,1,2 parseInt("023") 19 Radix defaults to 8 parseInt("0x23") 35 Radix defaults to

Falsy JavaScript

In continuation of my previous blog on the basic JavaScript expressions , this blog is about Falsy and Truthy values in JavaScript. When presented with a non boolean expression instead of a boolean value, JavaScript uses Truthy or Falsy values instead to determine the result. At first glance, this could be confusing and could lead to errors while scripting. var a = "someval"; var b; if (a) { // this is a truthy      // Block is executed } if (b) { // b is undefined and so a falsy      // Block is not executed } The Falsy Values All expressions, objects and values are Truthy by default. There are exceptions and they are called the Falsy values and are listed below:   # The empty string; ""   # null   # undefined   # The number 0   # NaN   # The boolean false It gets tricky If you see the below table, you will note that it gets tricky or rather one should be a little extra careful while dealing with Falsy values. Expression Value Falsy