Dorokhov.codes

String

Creating strings

const name = "Andrew";

Interpolation

Template strings.

const message = `Hello, ${name}!`; // Only this type of quotes.

Properties

s.length

Methods

s.toUpperCase();
s.toLowerCase();
s.indexOf('world'); // Find index of a substring.
s.trim(); // Removes whitespace from both ends of a string and returns a new string.
s.split(', '); // Split a string and return an array.
s.charCodeAt(); // Get a char code by an index.

Working with substrings:

// slice(indexStart, indexEnd)
s.slice(7, 10); // Substring from index 7 to index 10.
s.slice(7);     // Substring from index 7 to the end of the string.

// substring(indexStart, indexEnd)
s.substring(7, 10); // Substring from index 7 to index 10.
s.substring(7);     // Substring from index 7 to the end of the string.

// substr(start, length)
s.substr(7, 3); // Substring from index 7 and 3 symbols length

Get a char:

s[3]; // The fourth char of the string.

Static methods:

String.fromCharCode(); // Get a char(s) by its code(s).

Regular expressions

Flags:

  • i - case insensitive.
  • g - global (all matches).
  • m - multiline.

Special symbols:

  • . - any character.

Classes:

  • \d - numbers. \D - not numbers.
  • \w - word characters. \W - not word characters.
  • \s - space characters. \S - not space characters.
new RegExp('pattern', 'flags');
// Or:
/pattern/flags;

Find something in a string (get position):

const s = "Ann";
s.search(/n/);

Get array of matches:

s.match(/n/); // Only one.
s.match(/n/g); // All.

Replace substring:

s.replace(/n/g, '*');

Test regexp:

someRegExp.test(str); // Returns true of false.

Conversion to a string

String(15); // We will get a string type.
15 + '';    // We will get a string type.