本文介绍了确定Promises.all中最慢的承诺的处理方法,对大家解决问题具有一定的参考价值,需要的朋友们下面随着小编来一起学习吧!

问题描述

我一直在我的应用程序中使用Promise.all。
为了提高应用程序速度,如何确定哪个承诺最慢?

I have been using Promise.all in my app. For the purpose of improving app speed, how to determine which promise is the slowest?

const result = await Promise.all([
          this.props.fetchUser(),
          this.props.cacheResourcesAsync(),
          this.props.initAmplitude(),
          this.props.initAppVariables(),
        ]);


推荐答案

您可以为此使用辅助功能:

You can use a helper function for that:

async function time(p, name) {
    const start = Date.now();
    try {
        return await p;
    } finally {
        const end = Date.now();
        console.log(`${name} took ${end-start}ms`);
    }
}

然后写

const result = await Promise.all([
    time(this.props.fetchUser(), "user"),
    time(this.props.cacheResourcesAsync(), "cacheResources"),
    time(this.props.initAmplitude(), "amplitude"),
    time(this.props.initAppVariables(), "appVars"),
]);

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10-31 05:21