JavaScript - replace first 3 characters in string
In this article, we would like to show you how to replace the first 3 characters in string in JavaScript.
Quick solution
// ONLINE-RUNNER:browser;
let text = 'ABCD';
let result = 'xyz' + text.slice(3);
console.log(result); // xyzD
or:
// ONLINE-RUNNER:browser;
let text = 'ABCD';
let replacer = 'xyz';
let result = replacer.concat(text.slice(3));
console.log(result); // xyzD
or:
// ONLINE-RUNNER:browser;
let text = 'ABCD';
let result = text.replace(/^.{3}/g, 'xyz');
console.log(result); // xyzD
1. Using string slice() with + operator
In this example, we use string slice() method to remove the first 3 characters of the text string. Then with + operator we add the remainder of the text to the replacer.
Runnable example:
// ONLINE-RUNNER:browser;
let text = 'ABCD';
let replacer = 'xy';
let result = replacer + text.slice(3);
console.log(result); // xyD
Note:
The
replacerfor the three removed characters may cosist of any number of characters, not exactly 3.
2. Using string slice() with concat() method
In this example, we use string slice() method to remove the first 3 characters of the text string. Then with concat() method we add the remainder of the text to the replacer.
Runnable example:
// ONLINE-RUNNER:browser;
let text = 'ABCD';
let replacer = 'xy';
let result = replacer.concat(text.slice(3));
console.log(result); // xyD
Note:
The
replacerfor the two removed characters may cosist of any number of characters, not exactly 3.
3. Using string replace() with regex
In this example, we use string replace() with /^.{3}/g regex to replace the first 3 characters in the text string.
Regex explanation:
^- matches the beginning of the string,.- matches any character except linebreaks,{3}- matches the specified quantity of the previous token (in our case the.).
Runnable example:
// ONLINE-RUNNER:browser;
let text = 'ABCD';
let result = text.replace(/^.{3}/g, 'xyz');
console.log(result); // xyzD