My Blog

With this article, I want to quickly and simply explain the most important ways to convert JavaScript from one value type to another. Type casting is most often referred to as coercion. There are two types of coercion: explicit and implicit.

• Explicit coercion is usually obvious to the programmer who reads a part of JavaScript code.
• Implicit coercion is done more subtly and is not always obvious to the programmer, especially if they have not used an implicit coercion operation before.

Strings in JavaScript are immutable which means that once a string is defined, it cannot be changed anymore. Trying to change a string with a standard String-function will only create a new string and not affect the original string. Consider the following example, where the value in string1 is not changed:

var string1 = "LOREM IPSUM";
string1.toLowerCase();
console.log(string1);

Inspired from an exercise in Hackerrank.com, I found the opportunity to present you the data types that JavaScript defines, which are the following six:

• undefined
• null
• number
• string
• boolean
• object

Arrays and functions are plain objects in JavaScript and they both belong to the object data type.

Often I have to use a value from a variable and not a fixed string inside a regular expression. For example if I wanted to iterate over the english alphabet and find the number of occurrences of each letter inside a string, I had to do something like the following:

var testString = "Lorem ipsum dolor sit amet, consetetur sadipscing elitr.";
var matches = testString.match(/a/g).length;
// do this for all the remaining letters

the previous example would work and would find all occurrences of “a”.