In this tutorial, we will learn how to use JavaScript RegExp to perform case-insensitive matching.
Regular expressions can be declared in two ways -
Users can use the following syntax to create regular expressions.
//Using a regular expression literal const regex = /tutorial/i //Using RegExp constructor const regex2 = new RegExp('tutorial', 'i')
In the above syntax, the regular expression is created to match the word "tutorial", the modifier "i" means that it can match any substring with these characters, regardless of their case ("TuToRial", "Tutorial" ,wait).
The match() method is part of the String object in JavaScript. It is used to match strings with RegExp or regular expressions.
Users can use the match() method with JavaScript RegExp according to the following syntax to perform case-insensitive matching.
text.match(regex)
In the above syntax, "text" is a string that needs to be checked using a regular expression. "regex" is a regular expression pattern.
In the example given below, we use the match() method to perform case-insensitive matching. We are checking the match method result when the button is clicked and outputting it.
<html> <body> <h4>Performming Case Insensitive Matching with RegExp using <i> match() </i> method</h4> <button onclick="check()">Check</button> <p>Original Text: Welcome to Tutorialspoint</p> <p>Text To Match: tutorial </p> <p id="output"></p> <script> const text='Welcome to Tutorialspoint' const regex=/tutorial/i function check(){ //Using the match method let result=text.match(regex) document.getElementById('output').innerHTML='Mached Text: '+result } </script> </body> </html>
The above output shows that the match() method returns the matching substring "Tutorial".
The search() method is part of the String object in JavaScript. It is used to search for a substring of a string based on a RegExp or regular expression.
Users can use the search() method with JavaScript RegExp according to the following syntax to perform case-insensitive matching.
text.search(regex)
In the above syntax, "text" is a string and "regex" is a regular expression pattern.
In the example given below, we have used the search() method and on click of the button we are checking the result of the search() method and outputting it.
<html> <body> <h4>Performming Case Insensitive Matching with RegExp using <i> search() </i> method.</h4> <p>Text: Welcome to Tutorialspoint</p> <p>Text to Match: tutorial</p> <button onclick="check()">Check</button> <p id="output"></p> <p><b>Note:</b>The search() method returns the position of first match</p> <script> const text='Welcome to Tutorialspoint' const regex=/tutorial/i function check(){ //Using search method let result=text.search(regex) document.getElementById('output').innerHTML='Result: '+result } </script> </body </html>
In the above output, the user can see that the search() method returns the starting position of the substring "Tutorial".
The test() method is part of the RegExp object in JavaScript. It is used to test strings based on RegExp or regular expressions.
Users can use the test() method with JavaScript RegExp according to the following syntax to perform case-insensitive matching.
regex.test(text)
In the above syntax, "text" is a string that needs to be checked using a regular expression. "regex" is a regular expression pattern.
In the example given below, we have used the test() method.
<html> <body> <p>Performming Case Insensitive Matching with JavaScript RegExp using <i> test() </i> method</p> <p>Text: Welcome to Tutorialspoint</p> <p>Text to Match: tutorial</p> <button onclick="check()">Check</button> <p id="output"></p> <p><b>Note:</b> The test() method returns true if there is a match, else returns false.</p> <script> const text = 'Welcome to Tutorialspoint' const regex = /tutorial/i function check() { //Using the test method let result = regex.test(text) document.getElementById('output').innerHTML = 'Result: ' + result } </script> </body> </html>
In the above output, the user can see that the test() method returns true because the "Tutorial" substring is present in the text.
The exec() method is part of the RegExp object in JavaScript. It is used to match strings with RegExp or regular expressions.
Users can use the exec() method with JavaScript RegExp according to the following syntax to perform case-insensitive matching.
regex.exec(text)
In the above syntax, "text" is a string and "regex" is a regular expression pattern.
In the example given below, we have used the exec() method.
<html> <body> <p>Performming Case Insensitive Matching with JavaScript RegExp using <i> exec() </i> method</p> <button onclick="check()">Check</button> <p>Text: Welcome to Tutorialspoint</p> <p id="output"></p> <script> const text='Welcome to Tutorialspoint' const regex=/tutorial/i function check(){ //Using the exec method let result=regex.exec(text) document.getElementById('output').innerHTML='Result: '+result } </script> </body> </html>
The above output shows that the exec() method returns the matching substring "Tutorial".
In this tutorial, we discussed four ways to use RegExp to perform case-insensitive matching. The first two methods are the string match() and search() methods. The other two methods are the RegExp test() and exec() methods.
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