Maybe.fromEmpty?

[customcommander]

I was wondering if it would make sense to have this new static method?

Maybe.fromEmpty([]);
//=> None
Maybe.fromEmpty({});
//=> None
Maybe.fromEmpty('');
//=> None
Maybe.fromEmpty(null);
//=> None
Maybe.fromEmpty(undefined);
//=> None

It could (or perhaps should) delegate to fantasy-land/empty to work out if a given value is its type's empty value.

Use case:

I have a css rules object which contains css rules to apply to a string if there's any. Otherwise the string is returned as is. Problem is that the object may actually be "empty" i.e. it is an object but has no properties.

const styles = (css, text) =>
  Maybe
    .fromEmpty(css) // e.g. {'text-decoration': 'underline', 'color': 'red'}
    .map(obj => obj.entries()) // [['text-decoration', 'underline'], ['color', 'red']]
    .map(arr => arr.map(pair => pair.join(':'))) // ['text-decoration:underline', 'color:red']
    .map(arr => arr.join(';')) // 'text-decoration:underline;color:red'
    .fold(text)(str => `<span style="${str}">${text}</span>`);

styles({'font-style': 'italic'}, 'foo');
//=> '<span style="font-style:italic">foo</span>'

styles({}, 'foo');
//=> 'foo'

Any thoughts?

[ulfryk]

👍 great idea @customcommander I had one usecase just today :)

Can you implement it?

[customcommander]

I would love it. I'll give it a shot :)

[ulfryk]

snapshot released as monet@0.9.0-422