LANGUAGE » JAVASCRIPT

String

Last updated:
Reference:developer.mozilla.org

Basic ​

js
let str1 = 'Some string'
let str2 = `Value of a is ${a}`  // Template string [ES6]

// Regex
let reg1 = /[abc]/
let reg2 = new RegExp('[abc]')

Methods ​

js
str.substring(beginIndex, endIndex)
str.slice(beginIndex, endIndex)
str.substr(beginIndex, numChars)
str.trim()
str.split(separator)
str.replace(pattern, newPattern)  // first occurence
str.charAt(index)
str.toUpperCase()
str.toLowerCase()
str.endsWith(pattern)
str.padStart(targetLength, padString)
str.padEnd(targetLength, padString)

// Find index
str.indexOf(text)
str.search(reg)

// Existence of pattern
reg.test(text)

Techniques ​

Split by lines:

js
let lines = text.split(/\r?\n/)

Replace all:

js
let reg = /-/g  // Must have the g option
text.replace(reg, '')

text.split('-').join('')

Capitalize:

js
text.charAt(0).toUpperCase() + text.slice(1)

Add zeros to the left of a number:

js
String(1).padStart(2, '0')  // "01"