charAt() javascript
Javascript charAt() function of string object is used to find character at any index or position in a string.
Characters of a string are indexed where the index of first character is 0, second is 1 and so on. Index of last character of the string is equal to length of string – 1.

Javascript charAt() syntax
charAt() accepts a numeric integer and returns the character at that index. Note that returned value is also a string.

charAt(index)

where index is a number ranging from 0 to length of string – 1.
If the index is not in this range, an empty string is returned.

Default value of argument is 0. So, if you do not pass any value to charAt(), it is treated as 0 and the first character is returned.
Javascript charAt() example
Below is an example program to get the character at index 2 or third character from a string.  Example,

let str = 'Learning javascript';
console.log('Character at index 2 is: ' +str.charAt(2));

// with invalid index, return value will be ''
console.log('String with invald index is: '+str.charAt(-2));

This prints

Character at index 2 is: a
String with invalid index is:

To show that the return value of charAt() is a string, use typeof operator with the returned value. Example,

let str = 'Learning javascript'; 
let c = str.charAt(2);
console.log('charAt() returns a ' +typeof c);

Output at browser console is

charAt() returns a string

Get first character of string
There are two ways to get first character of a string with charAt().
1. Supply 0 as argumet to charAt().
2. Supply no value to charAt() since 0 is default.

Both the examples are given below

let str = 'Learning javascript';
let first = str.charAt(1);
console.log('First character with charAt(1) is: '+first);
first = str.charAt();
console.log('First character with charAt() is: '+first);

This prints

First character with charAt(1) is: L
First character with charAt() is: L

Get last character of string
Index of last character of string = its length – 1.
Length of a string can be determined using its length property. So, following code finds the last character of a string using charAt().

let str = 'Learning javascript';
let lastChar = str.charAt(str.length - 1);
console.log('Last character of string is: ' + lastChar);

which prints

Last character of string is: t

charAt() with decimal value
If a decimal value is supplied to charAt(), it ignores the decimal part and only integer value is considered.
Below example will prove this

let str = 'Learning javascript';
console.log('Character at position 2.4 is: '+str.charAt(2.4));
console.log('Character at position 2.5 is: '+str.charAt(2.5));
console.log('Character at position 2.7 is: '+str.charAt(2.5));
console.log('Character at position 2.9 is: '+str.charAt(2.9));

Output will always be same

Character at position 2.4 is: a
Character at position 2.5 is: a
Character at position 2.7 is: a
Character at position 2.9 is: a

Hope the article was useful.

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