How to get only specific metrics from Google Lighthouse?

Question

Let's suppose I'd only like to get the first-meaningful-paint metric from Google Lighthouse.

I'm using the below snippet of code, which does a full audit (which takes too long, since I'm only interested in one metric). How can I change the below code to tell Lighthouse to only get one metric for me?

(Source code snippet based on this)

const puppeteer = require('puppeteer');
const lighthouse = require('lighthouse');
const urlLib = require('url').URL;

async function run() {
    const browser = await puppeteer.launch({
        headless: false,
        defaultViewport: null
    });

    const { lhr } = await lighthouse("https://www.google.com", {
        port: (new urlLib(browser.wsEndpoint())).port,
        logLevel: 'info',
        output: 'json'
    });

    console.log(lhr);
}

run();

Answer 1

Inside the settings object of the configuration, you can specify which audits to run. When calling lighthouse, the configuration is provided as third argument (more information in the docs).

Code Sample

lighthouse('...', { /* ... */ }, {
  extends: 'lighthouse:default',
  settings: {
    onlyAudits: ['first-meaningful-paint'],
  }
});

This will only run the first-meaningful-paint audit.