RegExp Properties

Properties
- flags
- source
- lastIndex
- global
- ignoreCase
- multiline
- sticky
- unicode

Syntax - general

RegExPattern.PropertyNames

To run below examples, try it inside <script> tag, in a basic html file

flags

To get all the flags used in RegExp object

Syntax

RegExPattern.flags

For example :

var str="This Is a book";
var pattern=/is/ig;
alert(pattern.flags);
// Output: ig

Comment : Return used flags in pattern ('ig' in above case)

source

To get the pattern text

Syntax

RegExPattern.source

For example :

var str="This Is a book";
var pattern=/is/ig;
alert(pattern.source);
// Output: is

Comment : Return used pattern text ('is' in above case)

lastIndex

To get/set the index at which pattern starts the next match

Syntax - To get lastIndex

RegExPattern.lastIndex

Syntax - To set lastIndex

RegExPattern.lastIndex=indexNumber

Works only if the "g" or "y" flag is enabled
Default, always starts from index 0 & at the end set to 0
Used when you have to modify the index place

Note! You can only set lastIndex, when using "y" flag or exec() or test() method, otherwise it's of no use

For example :

var str="This Is a book";
var pattern=/is/ig;
alert(pattern.lastIndex); // start Output: 0

pattern.lastIndex=4;      // set the index value to 4
//  means start match from 4th index

while(pattern.test(str)==true){
  alert(pattern.lastIndex);   // Output: 7
}

// after index 7 their is no match left
alert(pattern.lastIndex); // end Output: 0

Comment : Returns index at which pattern start the next match

global

To check pattern is using 'g' (global) flag or not

Syntax

RegExPattern.global

For example :

var str="This Is a book";
var pattern=/is/ig;
alert(pattern.global);
// Output: true

Comment : check 'g' flag enabled or not ('true' in above case)

ignoreCase

To check pattern is using 'i' (ignoreCase) flag or not

Syntax

RegExPattern.ignoreCase

For example :

var str="This Is a book";
var pattern=/is/ig;
alert(pattern.ignoreCase);
// Output: true

Comment : check 'i' flag enabled or not ('true' in above case)

multiline

To check pattern is using 'm' (multiline) flag or not

Syntax

RegExPattern.multiline

For example :

var str="This Is a book";
var pattern=/is/ig;
alert(pattern.multiline);
// Output: false

Comment : check 'm' flag enabled or not ('false' in above case)

sticky

To check pattern is using 'y' (sticky) flag or not

Syntax

RegExPattern.sticky

For example :

var str="This Is a book";
var pattern=/is/ig;
alert(pattern.sticky);
// Output: false

Comment : check 'y' flag enabled or not ('false' in above case)

unicode

To check pattern is using 'u' (unicode) flag or not

Syntax

RegExPattern.unicode

For example :

var str="This Is a book";
var pattern=/is/ig;
alert(pattern.unicode);
// Output: false

Comment : check 'u' flag enabled or not ('false' in above case)

Methods

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Properties