Do more with Javascript Strings
Handling words and sentences is very important in programming.
Most things in JS are objects. String is one of them. So when we create a new String we get a bunch of properties and methods which helps us to perform various operations. Let’s explore some useful methods available in Javascript.
The code examples below are also available at Github
Length
To find length of a String we can use length property as follows
let message = 'Hello';
message.length
Get a Character
To get a specific character we can give the index in []message[3]
This will return ‘l’, quite like arrays. The first index location is 0.
0 1 2 3 4
H e l l o
Get index of a Substring
We can use indexOf() method to get the index of a substring.
let str1 = 'jackma';
str1.indexOf('ma') // prints 4
str1.indexOf('Jam') // prints -1
Extract a Substring
You can use the slice() method to extract a substring. You need to provide start and end indexes. The end index won’t be included.
let str1 = 'jackma';
str1.slice(2,3); // prints c
str1.slice(3,5); // prints km
If you don’t give end index then all characters from start index till end are extracted.
str1.slice(2); // prints ckma
Change the string case
To convert characters of a string to all lower case use toLowerCase()
str1.toLowerCase() // prints jackma
To convert characters of a string to all upper case use toUpperCase()
str1.toUpperCase() // prints JACKMA
Replace part of a String with another string
Let’s say we want to replace ‘get’ in ‘doget’ to ‘put’.
str2 = 'doget';
str2.replace('get', 'put') // prints doput
