mixin.js

/**
  Mixes in objects in `properties` into a class.
  To be used as a decorator.
  
  @mixin({...})
  class MyClass {...}
*/
function mixin(properties: {[key: string]: any}): Function {
    if (properties == null) {
        throw new Error(`Argument for 'properties' is required.`);
    }
    return function (target: any): any {
        if (typeof properties === 'object') {
            Object.keys(properties).forEach(name => {
                target.prototype[name] = properties[name];
            });
        }
        return target;
    };
}