evaluate

Type:

It evaluates the JavaScript stringified value provided inside the browser context over the target URL, returning the result.

It's quite similar to selector, but designed to specify the value to be obtained in a JavaScript-like way.


const mql = require('@microlink/mql')

const getNextVersion = url =>
  mql(url, {
    data: {
      version: {
        evaluate: 'window.next.version',
        type: 'string'
      }
    }
  })

const { data } = await getNextVersion('https://vercel.com')

console.log(`Next.js version is: ${data.version}`)

You can combine evaluate with types for data correcteness.

It can evaluate anything browser compatible in the JavaScript context.


const mql = require('@microlink/mql')

const getExcerpt = url =>
  mql(url, {
    data: {
      excerpt: {
        evaluate: async () => {
          const response = await window.fetch(
            'https://cdn.jsdelivr.net/npm/@mozilla/readability/Readability.js'
          )
          const script = await response.text()
          window.eval(script)
          const reader = new window.Readability(window.document)
          return reader.parse().excerpt
        },
        type: 'string'
      }
    }
  })

const { data } = await getExcerpt(
  'https://levelup.gitconnected.com/how-to-load-external-javascript-files-from-the-browser-console-8eb97f7db778'
)

console.log(data.excerpt)