group array of objects by key two deep level code example
Example: javascript group by key
result = array.reduce((h, obj) => Object.assign(h, { [obj.key]:( h[obj.key] || [] ).concat(obj) }), {})result = array.reduce((h, obj) => Object.assign(h, { [obj.key]:( h[obj.key] || [] ).concat(obj) }), {})