JavaScript replaces() method is used to replace the matched substring with a new substring. This returns a new string with the specified string/regex replaced.
string.replace(searchValue, newValue)
This method searches a string for a value or a regular expression.
JavaScript replace() method
Simple example code replaces the first occurrence.
<!DOCTYPE html>
<html lang="en">
<body>
<script>
const text = "Java is awesome. Java is fun."
let pattern = "Java";
// replace the first Java with JavaScript
let new_text = text.replace(pattern, "JavaScript");
console.log(new_text);
const message = "ball bat";
// replace the first b with T
let result = message.replace('b', 'T');
console.log(result);
</script>
</body>
</html>
Output:
Replace all occurrences
We can use a global search modifier with replace() method to replace all the match elements otherwise the method replace only the first match.
You need to use a regex with a g
switch (global search). For example, /Java/g
instead of /Java/
.
const text = "Java is awesome. Java is fun."
const res = text.replace(/Java/g, "JavaScript");
console.log(res);
Output: JavaScript is awesome. JavaScript is fun.
Case-Insensitive Replacement
JavaScript also provides ignore flag to make the method case-insensitive.
let text = "Mr Blue has a blue house and a blue car";
let result = text.replace(/blue/gi, "red");
console.log(result)
Output: Mr red has a red house and a red car.
Do comment if you have any doubts or suggestions on this JS string method topic.
Note: The All JS Examples codes are tested on the Firefox browser and the Chrome browser.
OS: Windows 10
Code: HTML 5 Version