Strings in Detail

Introduction to String

In JavaScript, use Strings to store Text. It is a primitive Data-Type.

• There are 3 ways to create strings

1. Single quote:-

const single = 'This is a string.';
console.log(single);

2. Double quote:-

const double = "This is a string.";
console.log(double);

3. Backticks:-

const backtick = `This is a string.`;
console.log(backtick);

• The Backslash \ escape character turns special character into string character:

Code	Result	Description
\'	'	Single Quote
\"	"	Double Quote
\\	\	Backslash

String Methods

• string.length

  return the number of characters in a string.

• string[index]

  get a certain character of a string.

• string.toLowerCase

  return a lowercased string.

• string.toUpperCase

  return an uppercased string.

• string.includes('substring')

  checks whether a substring exists inside of a string [check the character case]

• string.indexOf(searchValue)

  returns the index of the first occurrence of the specified value, starting the search at fromIndex. Returns -1 if the value is not found.

• string.lastIndexOf(searchValue)

  returns the index of the last occurrence of the speciffied value, searching backwards from fromIndex. Returns -1 if the value is not found.

• string.startsWith('substring')

  The startsWith() method returns true if string with specified string, otherwise it returns false.

• string.endsWith('substring')

  The endsWith() method returns if a string ends with a specified string, otherwise it returns false.

• string.slice(start, end)

  The slice() method extracts a part of a string and return it as a new string without modifying the original string. The start and end parameter specifies the part of the string to extract.

• string.split('')

  It returns an array of characters of a string.

• string.split(' ')

  It returns an array of words of a string.

• string.repeat(count)

  It returns a string with a number of copies of a string.

• string.trim()

  It removes the whitespace from both sides of a string.

• string.charAt(index)

  It returns the character at a specified index (position) in a string.

• string.replace(substr, newSubstr)

  It returns a new string with a substring (substr) replaced by a new one (newSubstr).

• string.substr(strat, length)

  It returns a portion of the string, starting at the specified index and extending for a given number.