String

General

Info:

• Strings are written with quotes. You can use single or double quotes:

  let carName1 = "Volvo XC60";
  let carName2 = 'Volvo XC60';

• escaping chars in a String

  • quotes: "" or ''

    // Single quote inside double quotes:
    let answer1 = "It's alright";
    
    // Single quotes inside double quotes:
    let answer2 = "He is called 'Johnny'";
    
    // Double quotes inside single quotes:
    let answer3 = 'He is called "Johnny"';
    
    let text = "We are the so-called \"Vikings\" from the north.";
    
    let text= 'It\'s alright.';

  • backslash \

    let text = "The character \\ is called backslash.";

  • other chars designed to control typewriters, teletypes, and fax machines

    \b Backspace

    \f Form Feed

    \n New Line

    \r Carriage Return

    \t Horizontal Tabulator

    \v Vertical Tabulator

• wrap up a code line within a text string with a +:

  document.getElementById("demo").innerHTML = "Hello " +
  "Dolly!";

Danger:

• Do not create Strings objects.

  The new keyword complicates the code and slows down execution speed.

  String objects can produce unexpected results:

  Note the difference between (x==y) and (x===y).

  When using the == operator, x and y are equal:

  let x = "John";
  let y = new String("John"); // true
  When using the === operator, x and y are not equal:

  let x = "John";
  let y = new String("John"); // false

• Comparing two JavaScript objects always returns false.

Methods

length

• To find the length of a string, use the built-in length property:

  let text = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
  let length = text.length;