editor-component-benchmark.js

const fs = require('fs')

global.profileEditor = async function () {
  const sampleText = fs.readFileSync('/Users/nathan/src/atom/spec/fixtures/sample.js', 'utf8') + '\n'

  // await profileScrollFullScreen()
  // await timeoutPromise(500)
  // await profileScrollHalfScreen()
  // await timeoutPromise(500)
  await profileCharacterInsertion()

  async function profileScrollFullScreen () {
    const editor = await openEditor()
    const {component} = editor

    console.time('scroll full screen')
    for (let i = 0; i < 50; i++) {
      if (i % 2 === 0) {
        component.setScrollBottom(component.getScrollHeight())
        await updateComponent(component)
      } else {
        component.setScrollTop(0)
        await updateComponent(component)
      }
    }

    console.timeEnd('scroll full screen')
    editor.destroy()
  }

  async function profileScrollHalfScreen () {
    const editor = await openEditor()
    const {component} = editor

    console.time('scroll half screen')
    for (let i = 0; i < 50; i++) {
      component.setScrollTop(component.getScrollTop() + component.getScrollContainerClientHeight() / 2)
      await updateComponent(component)
    }
    console.timeEnd('scroll half screen')

    editor.destroy()
  }

  async function profileCharacterInsertion () {
    const editor = await openEditor()
    const {component} = editor

    editor.setCursorScreenPosition([3, Infinity])

    console.time('insert and delete character')
    for (let i = 0; i < 50; i++) {
      editor.insertText('//')
      await updateComponent(component)
      await timeoutPromise(10)
      editor.backspace()
      editor.backspace()
      await updateComponent(component)
      await timeoutPromise(10)
    }
    console.timeEnd('insert and delete character')

    editor.destroy()
  }

  function timeoutPromise (timeout) {
    return new Promise(function (resolve) {
      window.setTimeout(resolve, timeout)
    })
  }

  async function openEditor () {
    await atom.workspace.open('/tmp/test.js')
    const editor = atom.workspace.getActiveTextEditor()
    editor.setText(sampleText.repeat(100))
    return new Promise((resolve) => {
      editor.onDidTokenize(() => resolve(editor))
    })
  }

  function updateComponent (component) {
    component.scheduleUpdate()
    return component.getNextUpdatePromise()
  }
}