Handling Strings and Arrays in JavaScript

Author : Doe Hoon LEE

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Strings and Arrays in JavaScript

The most obvious difference is the way they look

const myString = "DGTechBlog";
const myArray = ["D", "G", "T", "e", "c", "h", "B", "l", "o", "g"];

Strings are encapsulated with " " and Arrays are encapsulated with [ ]

One of the ways to find out the data type is to use typeof

const myString = "DGTechBlog";
const myArray = ["D", "G", "T", "e", "c", "h", "B", "l", "o", "g"];

typeof myString // => "string"
typeof myArray // => "object"

Another difference would be that Arrays can contain any data type. However, Strings cannot!

const dataTypes = ["String", 0, NaN, ["A","R","R","A","Y"]]

How can I access?

Let’s find out 3rd item in both

const myString = "DGTechBlog";
const myArray = ["D", "G", "T", "e", "c", "h", "B", "l", "o", "g"];

myString.charAt(3) // => "e"
myArray[3] // => "e"

Most commonly used techniques for Strings

length returns the length of the String

indexOf(WHAT_YOU_ARE_LOOKING_FOR) returns the index of the string you are looking for or -1 if there is no match

method	returns
“START STRING”.startsWith(“SART”)	true
“END STRING”.endsWith(“STRING”)	true
“END STRING”.endsWith(“END”)	false

slice(HERE,THERE) returns the string index from HERE to THERE or from HERE to the end if not specified

Fun fact! if you type in a negative number in slice()

"STRING".slice(-2) // => "NG"

What it does is string.length + (-2) = 6 + (-2) = 6 -2 = 4 => "STRING".slice(4)