class Test {

    constructor() {
        this.processData({}).then((data) => {
            console.log(data);
        })
    }

    async processData(data) {
        data = await this.one(data);
        console.log('one');
        data = await this.two(data);
        console.log('two');
        data = await this.three(data);
        console.log('three');
        return data;
    }

    one(data) {
        return new Promise((resolve, reject) => {
            setTimeout(() => {
                data.foo = 11;
                data.bar = 42;
                resolve(data);
            }, 2000);
        });
    }

    two(data) {
        return new Promise((resolve, reject) => {
            setTimeout(() => {
                if (data.hasOwnProperty('foo')) {
                    Object.keys(data).forEach((key) => {
                        data[key] = 2 * data[key];
                    });
                    resolve(data);
                } else {
                    reject('wtf');
                }
            }, 500);
        })
    }

    three(data) {
        return new Promise((resolve, reject) => {
            setTimeout(() => {
                data.qux = Object.keys(data).reduce((result, key) => {
                    return result + data[key];
                }, 0);
                resolve(data);
            }, 1000);
        })
    }

}

module.exports = new Test();