wiki/content/20201104102343-javascript_regexp_replace_method.md

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---
id: 11d0fefd-c11e-400b-80fd-ba40e94b2a47
title: JavaScript RegExp Replace Method
---
replace[^1] is a nice way to use regexps to replace text:
``` javascript
console.log("papa".replace("p", "m"));
console.log("Borobudur".replace(/[ou]/, "a"));
console.log("Borobudur".replace(/[ou]/g, "a"));
```
You can also use awk like syntax to switch things around:
``` javascript
console.log(
"Liskov, Barbara\nMcCarthy, John\nWadler, Philip"
.replace(/(\w+), (\w+)/g, "$2 $1"));
```
You can even pass a function to replace:
``` javascript
let s = "the cia and fbi";
console.log(s.replace(/\b(fbi|cia)\b/g,
str => str.toUpperCase()));
```
``` javascript
let stock = "1 lemon, 2 cabbages, and 101 eggs";
function minusOne(match, amount, unit) {
amount = Number(amount) - 1;
if (amount == 1) { // only one left, remove the 's'
unit = unit.slice(0, unit.length - 1);
} else if (amount == 0) {
amount = "no";
}
return amount + " " + unit;
}
console.log(stock.replace(/(\d+) (\w+)/g, minusOne));
```
# Footnotes
[^1]: <https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Symbol/replace>