NCBI-written gatherer for ncbi_app meta

ncbi_app-gatherer.js

"use strict";

const Gatherer = require("lighthouse").Gatherer;

/**
 * @fileoverview Extracts `window.myLoadMetrics` from the test page.
 */

class NCBIAppMeta extends Gatherer {
  async afterPass(options) {
    const driver = options.driver;
    const expression = `(function() {
        var meta = document.querySelector("meta[name=ncbi_app]");
        ret = {name: false, content: false};
        var content;
        if (meta) {
            content = meta.getAttribute("content");
            ret.name = true;
            ret.content = content && content.length > 3;
        }
        return ret;
    })()`;
    return await driver.evaluateAsync(expression);
  }
}

module.exports = NCBIAppMeta;

In general we try to write gatherers to just get the information and not pass the judgement yet, so for example this might return the content attribute value or null if it didn't exist and then the audit would check that it's length is > 3. If you think it's unlikely the test will ever change, this works too.

OK I kind of figured. Thanks for taking a look!