JavaScript - replace first character in string
In this article, we would like to show you how to replace the first character in string in JavaScript.
Quick solution
// ONLINE-RUNNER:browser;
let text = 'ABC';
let result = 'x' + text.slice(1);
console.log(result); // xBC
or:
// ONLINE-RUNNER:browser;
let text = 'ABC';
let replacer = 'x';
let result = replacer.concat(text.slice(1));
console.log(result); // xBC
or:
// ONLINE-RUNNER:browser;
let text = 'ABC';
let result = text.replace(/^./g, 'x');
console.log(result); // xBC
1. Using string slice()
with +
operator
In this example, we use string slice()
method to remove the first character of the text
string. Then with +
operator we add the remainder of the text
to the replacer
.
Runnable example:
// ONLINE-RUNNER:browser;
let text = 'ABC';
let replacer = 'x';
let result = replacer + text.slice(1);
console.log(result); // xBC
Note:
The
replacer
for the removed character may cosist of any number of characters, not exactly one.
2. Using string slice()
with concat()
method
In this example, we use string slice()
method to remove the first character 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 = 'ABC';
let replacer = 'x';
let result = replacer.concat(text.slice(1));
console.log(result); // xBC
Note:
The
replacer
for the removed character may cosist of any number of characters, not exactly one.
3. Using string replace()
with regex
In this example, we use string replace()
with /^./g
regex to replace the first character in the text
string.
Regex explanation:
^
- matches the beginning of the string,.
- matches any character except linebreaks.
Runnable example:
// ONLINE-RUNNER:browser;
let text = 'ABC'
let result = text.replace(/^./g, 'x');
console.log(result); // xBC