[koolba]

Curious why?

I get the usefulness for arrays and object declarations. Particular to have cleaner diffs. But why for function calls?

[t1amat]

Prettifying long function signatures and calls. You can spread them across multiple lines with the same trailing comma syntax you might use with a multiline array or object literal.

[epidemian]

> Particular to have cleaner diffs. But why for function calls?

Exactly the same reason :)

[koolba]

I suppose but that's usually an indication that an object would be more apt. If you have enough parameters that it needs to be wrapped, they're probably hard to track too.

[piezoney]

Well no, since you can use object destructuring.

const fn = ( { arg1 = '', arg2 = [], arg3 = true } = {} ) => { }

[scottmf]

But isn't this already valid with trailing commas?

[yzmtf2008]

One small benefit is that it's now easier to generate code.

[hajile]

I like it for `compose()` function calls. Changing the parameters and order is fairly common, so the trailing comma becomes convenient for moving and adding parameters.