Regular Expressions (Regex) in JavaScript

Regular expressions are used to perform pattern matching and search, replace, etc. functions on the text and perform validation.

Extracting the data from text and sentences or validating those texts to any specific pattern is important in programming. The javascript has many regular expressions (patterns) that will make the programming easy.

Here is the general syntax for Regex,

SYNTAX: 

/pattern/modifiers;

EXAMPLE:

Here is  the example for the general syntax of the Regex,

/SpeakingEnglish/i;

- Using string search()  with a regex in javascript.

To perform case insensitive searching in a string. And it searches for the position of the character.

It will search for the specified value of the string and will return the matched position of that string.

Here is an example for searching the string that starting with a capital letter:

let reg = "They speak English at work";
let result = reg.search(/English/i);
console.log(result);

OUTPUT : 11

Here is an example for searching the string starting with the small letter:

let reg = "They are speaking Spanish at work";
let result = reg.search(/english/i);
console.log(result);

OUTPUT : 11

- Using the test() method with a regex in javascript

The Test() method searches a string for a pattern, and after checking the result it will return true or false. The result depends on the result of the checking.

Here is an example for searching a string for the character "s":
let reg = "They speak English at work";
let pattern = /s/;
let result = pattern.test(reg);
console.log(result)

OUTPUT : true

let reg = "They speak English at work";
let pattern = /z/;
let result = pattern.test(reg);
console.log(result)

OUTPUT : false

- Using string replace()  with a regex in javascript.

Replace() regular expression perform the replacing of a specific value with another value.

If we want to change a value with a specific value, we can use this method.

Here is an example of this:

let reg = "They speak English at work";
let result = reg.replace(/english/i,"Hindi");
console.log(result)

OUTPUT: "They speak Hindi at work"

REGEX MODIFIERS IN JAVASCRIPT

In javascript, we use many modifiers in regular expressions to make the programming easy.

Here are some common javascript modifiers like Case insensitive,multi-line, global, etc.

let reg = "VisitCybrosys Technologies";
let result =reg.match(/cybrosys/i);
console.log(result)
 
OUTPUT:
//[object Array] (1)
["Cybrosys"]

REGEX PATTERNS IN JAVASCRIPT

Here explains some common patterns in the javascript like Brackets, Metacharacters, Quantifiers, etc.

BRACKETS

Bracket modifiers are used to find the range of characters in the text. Many bracket modifiers are in javascript regular expressions. Here explain some common bracket modifiers.

METACHARACTERS

Metacharacters are regular expression patterns with a special meaning. This makes the programming easy.

The basic regular expression in javascript and their applications are listed above. Try out each feature to learn more about them.