Group attributes

[reecefenwick]

Follow example of react-select https://codesandbox.io/s/w6n5llr6kl?module=/example.js

Though there seems to be a bug, I added a "group" to the options prop on FacetedSelect and changed the behaviour of buildOptions() to:

            // sort options by group
            const groupedOptions = new Map();
            for (const o of options) {
                const group = o.group || 'Other';
                const optionsForGroup = groupedOptions.get(group) || [];
                optionsForGroup.push({
                    value: o.label,
                    label: o.label,
                    getSuggestions: o.getSuggestions
                });
                groupedOptions.set(group, optionsForGroup);
            }
            return Array.from(groupedOptions).map(([key, value]) => {
                return {
                    label: key,
                    options: value
                }
            });

Resulting in:

Uncaught TypeError: Cannot read property 'toLowerCase' of undefined
at compareOption (Creatable.js:40)
at Creatable.js:51
at Array.some ()
at isValidNewOption (Creatable.js:50)
at Creatable.componentWillReceiveProps (Creatable.js:133)
at callComponentWillReceiveProps (react-dom.development.js:11528)
at updateClassInstance (react-dom.development.js:11720)
at updateClassComponent (react-dom.development.js:13154)
at beginWork (react-dom.development.js:13825)
at performUnitOfWork (react-dom.development.js:15864)

Some related issues:

1. [V2] Cannot use Createable together with custom getOptionLabel, getCustomValue JedWatson/react-select#2888
2. [V2] Creatable doesn't use getOptionValue and getOptionLabel props JedWatson/react-select#2630

This feature can be implemented in a non-breaking way so its not urgent