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Naftali Murgor
Naftali Murgor

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Introduction to JavaScript Strings

Introduction

JavaScript Strings provide a way of representing and handling characters.

JavaScript Strings

A JavaScript string is a set of character(s) written inside quotes.

// with single quote
let emptyString = '' // an empty string
let name = 'Elon Musk'

// with double quotes
let project = "SpaceX"
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Declaring a String in JavaScript does not restrict usage of single '' and double quotes ""

Acess character

String objects provide a useful method for accessing a character in a string

let catName = 'Anita'
console.log(catName.charAt(0)) // prints 'A', character at a position 0
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Strings behave like Array-like objects, so above can be:

let catName = 'Anita'
console.log(catName[0])// prints 'A'
// looping throug each character
for (let i = 0; i < catName.length; i ++) {
  console.log(catName[i]) // A, n, i, t, a
}
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Get length of a JavaScript String

const THREAD_NAME = 'Moonspiracy'
console.log(THREAD_NAME.length) // prints number of characters// 11
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Summary

JavaScript Strings provide a way of presenting strings using double or single quotes. Both syntaxes are valid and usage is based on project style guide and preferences.

Top comments (9)

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lukeshiru profile image
Luke Shiru

Adding to the article, you can also use " besides ' to define a string:

const obiWan = "hello there";
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And to loop over the characters in a string you have other options such as...

const greeting = "hello";

// Using for..of
for (const character of greeting) {
    console.log(character);
}

// Using Array.prototype.forEach (after turning it into an array with Array.from)
Array.from(greeting).forEach(character => console.log(character));

// Same with spread:
[...greeting].forEach(character => console.log(character));

// Same with Array.prototype.split
greeting.split("").forEach(character => console.log(character));
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And if you wonder which one is faster, here you have a perf comparison (you might think is the for..of ... and you would be wrong).

Cheers!

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romeerez profile image
Roman K • Edited

There is something interesting about turning a string to array, would you like a quiz?

// all are true:
typeof x == 'string'
x.length == 2;
[...x].length == 1
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What was the x? :)

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lukeshiru profile image
Luke Shiru

IDK if this is for me, but I take it: x was a UTF character made of others, like emojis with skin colors. You can use Intl.Segmenter to avoid this issue.

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romeerez profile image
Roman K • Edited

Was for you, okay I'll mention next time, you're right!

x = "💩"
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thanks for the link - I never heard of Segmenter

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naftalimurgor profile image
Naftali Murgor

Great insight!

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pengeszikra profile image
Peter Vivo • Edited

The new .at also works in String ... but not in IE

'Elon Musk'.at(-1) // k

'Elon Musk'.slice(-4) // Musk
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Maybe you can write about regexp which is great tool of string handling.

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naftalimurgor profile image
Naftali Murgor

Great insight! Never occured to me. I think IE is the "lost sheep" of web browsers haha

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