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JavaScript string methods

Here's a cheatsheet of the latest ECMAScript string methods in Markdown format: String.prototype.at(index: number) Will get character at certain index in a string. 'hello'.at(0) Results: 'h' String.prototype.charAt(index: number) Returns the character at a specified index (position) in a string. 'hello'.charAt(0) Results: 'h' String.prototype.charCodeAt(index: number) Returns the code of the character at a specified index in a string. 'hello'.charCodeAt(0) Results: 72 (The Unicode of 'H') String.prototype.padStart(targetLength: number, padString: string) Pads another string (multiple times) until the resulting string reaches the given length. '5'.padStart(4, '0') Results: '005' String.prototype.padEnd(targetLength: number, padString: string) Pads another string (multiple times) until it reaches a given length. '5'.padEnd(4, '0') Results: '5000' String.prototype.repeat(count: number) Returns a new string with a specified number of copies of the string it was called on. 'hello'.repeat(2) Results: 'hellohello' String.prototype.trim() Removes whitespace from both sides of a string. ' Hello World '.trim() Results: 'Hello World' String.prototype.trimStart() Removes whitespace only from the start of a string. ' Hello World '.trimStart() Results: 'Hello World ' String.prototype.trimEnd() Removes whitespace only from the end of a string. ' Hello World '.trimEnd() Results: ' Hello World' String.prototype.replace(searchValue: string | RegExp, replacement: string | (substring: string, ...args: any[]) => string) Searches a string for a specified value, or a regular expression, and returns a new string where the specified values are replaced. 'Hello World'.replace('World', 'there') Results: 'Hello there' String.prototype.match(regexp: RegExp) Searches a string for a match against a regular expression, and returns the matches. 'The rain in SPAIN stays mainly in the plain'.match(/ain/gi) Results: ['ain', 'AIN', 'ain', 'ain'] String.prototype.search(regexp: RegExp) Searches a string for a specified value, or regular expression, and returns the position of the match. 'Hello World'.search('World') Results: 6 String.prototype.slice(start?: number, end?: number) Extracts a part of a string and returns the extracted part in a new string. 'Apple, Banana, Kiwi'.slice(7, 13) Results: 'Banana' String.prototype.split(separator?: string | RegExp, limit?: number) Splits a string into an array of substrings. 'How are you doing today?'.split(' ') Results: ['How', 'are', 'you', 'doing', 'today?']

Mar 6, 2025 - 03:26
 0
JavaScript string methods

Here's a cheatsheet of the latest ECMAScript string methods in Markdown format:

  • String.prototype.at(index: number) Will get character at certain index in a string. 
  'hello'.at(0)

Results: 'h'

  • String.prototype.charAt(index: number) Returns the character at a specified index (position) in a string. 
  'hello'.charAt(0)

Results: 'h'

  • String.prototype.charCodeAt(index: number) Returns the code of the character at a specified index in a string. 
  'hello'.charCodeAt(0)

Results: 72 (The Unicode of 'H')

  • String.prototype.padStart(targetLength: number, padString: string) Pads another string (multiple times) until the resulting string reaches the given length. 
  '5'.padStart(4, '0')

Results: '005'

  • String.prototype.padEnd(targetLength: number, padString: string) Pads another string (multiple times) until it reaches a given length. 
  '5'.padEnd(4, '0')

Results: '5000'

  • String.prototype.repeat(count: number) Returns a new string with a specified number of copies of the string it was called on. 
  'hello'.repeat(2)

Results: 'hellohello'

  • String.prototype.trim() Removes whitespace from both sides of a string. 
  '   Hello World   '.trim()

Results: 'Hello World'

  • String.prototype.trimStart() Removes whitespace only from the start of a string. 
  '   Hello World   '.trimStart()

Results: 'Hello World '

  • String.prototype.trimEnd() Removes whitespace only from the end of a string. 
  '   Hello World   '.trimEnd()

Results: ' Hello World'

  • String.prototype.replace(searchValue: string | RegExp, replacement: string | (substring: string, ...args: any[]) => string) Searches a string for a specified value, or a regular expression, and returns a new string where the specified values are replaced. 
  'Hello World'.replace('World', 'there')

Results: 'Hello there'

  • String.prototype.match(regexp: RegExp) Searches a string for a match against a regular expression, and returns the matches. 
  'The rain in SPAIN stays mainly in the plain'.match(/ain/gi)

Results: ['ain', 'AIN', 'ain', 'ain']

  • String.prototype.search(regexp: RegExp) Searches a string for a specified value, or regular expression, and returns the position of the match. 
  'Hello World'.search('World')

Results: 6

  • String.prototype.slice(start?: number, end?: number) Extracts a part of a string and returns the extracted part in a new string. 
  'Apple, Banana, Kiwi'.slice(7, 13)

Results: 'Banana'

  • String.prototype.split(separator?: string | RegExp, limit?: number) Splits a string into an array of substrings. 
  'How are you doing today?'.split(' ')

Results: ['How', 'are', 'you', 'doing', 'today?']

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