react-app-shell/activity/src/store/global-store.js

react打包脚本和example, 这里的版本请忽略

import {observable, action} from 'mobx';

class GlobalStore {
    @observable promotion_file = '';

    @action set_promotion_file = str => {
        this.promotion_file = str;
    }
}

export default new GlobalStore();