Here's what I need:

```
121 => 121
14231.439400000 => 14,231.4394
1.123456789 => 1.12345679
-9012.4430001 => -9,012.4430001

```

I've tried the following: `return input.toFixed(8).toLocaleString().replace(/0*$/, '').replace(/\.$/, '');`

and that doesn't add commas. I've also looked at `numeraljs`, but that doesn't have the decimal features I require (specifying up to 8 decimals out, or trimming)

Any help?