---
title: Check yes/no string
type: snippet
language: javascript
tags: [string,regexp]
unlisted: true
cover: fort-lamp
dateModified: 2021-01-04T13:04:15+02:00
---

Returns `true` if the string is `'y'`/`'yes'` or `false` if the string is `'n'`/`'no'`.

- Use `RegExp.prototype.test()` to check if the string evaluates to `'y'`/`'yes'` or `'n'`/`'no'`.
- Omit the second argument, `def` to set the default answer as `'no'`.

```js
const yesNo = (val, def = false) =>
  /^(y|yes)$/i.test(val) ? true : /^(n|no)$/i.test(val) ? false : def;
```

```js
yesNo('Y'); // true
yesNo('yes'); // true
yesNo('No'); // false
yesNo('Foo', true); // true
```