Replace a comma with a Dot using JavaScript

Replace a comma with a Dot in JavaScript #

Use the replaceAll() method to replace all commas with dots, e.g. str.replaceAll(',', '.'). The replaceAll method returns a new string where all the matches are replaced by the provided replacement.

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const str1 = '123,456,789';

// ✅ Replace ALL Commas with Dots
const replaced1 = str1.replaceAll(',', '.');
console.log(replaced1); // 👉️ 123.456.789

// ✅ Replace FIRST comma with Dot
const replaced2 = str1.replace(/,/, '.');
console.log(replaced2); // 👉️ 123.456,789

// ✅ Replace ALL commas with Dot using Regex
const replaced3 = str1.replace(/,/g, '.');
console.log(replaced3); // 👉️ 123.456.789

The first example uses the String.replaceAll method to replace all commas in a string with a dot.

The 2 parameters we passed tot he replaceAll method are:

1. a substring that we want to match in the string
2. a replacement for each match

The replaceAll method returns a new string where all of the matches are replaced by the provided replacement.

The second example uses the String.replace method to replace the first occurrence of a comma in a string with a dot.

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const str1 = '123,456,789';

// ✅ Replace FIRST comma with Dot
const replaced2 = str1.replace(/,/, '.');
console.log(replaced2); // 👉️ 123.456,789

The first parameter we passed to the replace method is a regular expression.

All we try to match in our regular expression is a single comma.

By default the replace method replaces the first occurrence of the matched regular expression with the provided replacement string.

An alternative to the replaceAll method is to use the replace method with the g (global) flag.

To replace all commas with dots, call the replace() method with the following regular expression /,/g, e.g. str.replace(/,/g, '.'). The replace method will return a new string with all commas replaced by dots.

Copied!
const str1 = '123,456,789';

// ✅ Replace ALL commas with Dot using Regex
const replaced3 = str1.replace(/,/g, '.');
console.log(replaced3); // 👉️ 123.456.789

We used the g (global) flag, because we want to match all occurrences of a comma in the string and not just the first occurrence.

My personal approach is to always use the replaceAll method where possible, because not all developers are familiar with regular expressions.

If you ever need help reading a regular expression, bookmark this regex cheatsheet from MDN. It's by far the best one out there.

Further Reading #

• Create an Object from Two Arrays in JavaScript
• Convert an Array to JSON using JavaScript