JS String Basic Methods

Basic String Methods

Javascript strings are primitive and immutable: All string methods produces a new string without altering the original string.

String length String charAt() String charCodeAt() String at() String [ ] String slice() String substring() String substr() See Also: String Search Methods String Templates	String toUpperCase() String toLowerCase() String concat() String trim() String trimStart() String trimEnd() String padStart() String padEnd() String repeat() String replace() String replaceAll() String split()

let text = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
let length = text.length;
 
let char = text.charAt(0);
//The method returns a UTF-16 code (an integer between 0 and 65535).
let char = text.charCodeAt(0);
// The `at()` method is supported in all modern browsers since March 2022:
// It allows the use of negative indexes while `charAt()` do not.
let letter = name.at(2);
// If no character is found, [ ] returns undefined,
// while charAt() returns an empty string.
let letter = name[2];
text[0] = "A"; // Gives no error, but does not work
// slice(start, end)      allow neg index
// substring(start, end)  values less than 0 are treated as 0
// substr(start, length)  second param specifies the length of the extracted part.
let text = "Apple, Banana, Kiwi";
let part = text.slice(7, 13);
let part = str.substring(7, 13);
let part = str.substr(7, 6);
 
// `concat()` joins two or more strings:
let text3 = text1.concat(" ", text2);
 
let text = "5";
// Pad a string with "0" until it reaches the length 4:
let padded = text.padStart(4, "0");
 
let text = "Hello world!";
let result = text.repeat(2);
 
// The `replace()` method replaces **only the first** match
// If you want to replace all matches, use a regular expression with the /g flag set.
let text = "Please visit Microsoft and Microsoft!";
let newText = text.replace("Microsoft", "W3Schools");
// To replace case insensitive, use a **regular expression** with an `/i` flag (insensitive):
let newText = text.replace(/MICROSOFT/i, "W3Schools");
// To replace all matches, use a **regular expression** with a `/g` flag (global match):
let newText = text.replace(/Microsoft/g, "W3Schools");
let text = text.replaceAll("cats", "dogs");
let text = text.replaceAll(/Cats/g, "Dogs");
 
// If the separator is omitted, the returned array will contain the whole string in index [0].
// If the separator is "", the returned array will be an array of single characters:
let x = text.split("|");
let x = text.split("");