// FIXME: Mutable param should be forbidden in static lang.
function _mix(dist: Base & Source, obj: Source): void {
for (const key in obj) {
if (obj.hasOwnProperty(key) && key !== 'constructor' && obj[key] !== undefined) {
(dist)[key] = obj[key];
}
}
}
export default function mix(dist: Base & A & B & C, src1?: A, src2?: B, src3?: C): Base & A & B & C {
if (src1) _mix(dist, src1);
if (src2) _mix(dist, src2);
if (src3) _mix(dist, src3);
return dist;
}