trim()

The trim() method removes all leading (at the beginning) and trailing (at the end) space characters.

const name = "Hemanta    "

console.log(name.trim())
// "Hemanta"

startWith() & endsWith( )

The .startsWith(substring) method returns true when the substring is found at the beginning of the string, and false otherwise.

The .endsWith(substring) works the same but for the end of the string.

const greeting = "Hello World! I am learning React!"

console.log(greeting.startsWith("hello"))
// false

console.log(greeting.startsWith("Hello"))
// true

console.log(greeting.endsWith("!"))
// true

console.log(greeting.endsWith("Hello"))
// false

includes()

The .includes(substring) method returns true when the substring can be found anywhere in the string, and false otherwise.

const greeting = "Hello World! I am learning React!"

console.log(greeting.includes("Worl"))
// true

console.log(greeting.includes("!"))
// true

console.log(greeting.includes("Preact"))
// false

split()

The .split(separator) method divides the string into an array by splitting it with the separator you provide. For example:

const audio = "Sony, Sennheiser, AKG"

const audioArray = audio.split(",")

console.log(audioArray)
// [ 'Sony', ' Sennheiser', ' AKG' ]

Note that the opposite of String.split(separator) is Array.join(glue) method.

replace()

The .replace(search, replace) method returns a new string where the first occurence of the search parameter you provide is replaced by the replace parameter.

const greeting = "Hello World! I am loving React!"

const newGreeting = greeting.replace("!", ".")

console.log(greeting)
// Hello World! I am loving React!

console.log(newGreeting)
// Hello World. I am loving React!

Note that the replace() method only replaces the first match.