# Min array value based on function

JavaScript, Math, Array · Oct 21, 2020

Returns the minimum value of an array, after mapping each element to a value using the provided function.

- Use
`Array.prototype.map()`

to map each element to the value returned by`fn`

. - Use
`Math.min()`

to get the minimum value.

```
const minBy = (arr, fn) =>
Math.min(...arr.map(typeof fn === 'function' ? fn : val => val[fn]));
```

```
minBy([{ n: 4 }, { n: 2 }, { n: 8 }, { n: 6 }], x => x.n); // 2
minBy([{ n: 4 }, { n: 2 }, { n: 8 }, { n: 6 }], 'n'); // 2
```