somtodaynt/content/js/index.js

console.log('Somtoday\'nt content script active')

function changeSlogan (message) {
  if (message === 'reload') {
    location.reload()
  } else {
    const tonight = message[0]
    const slogans = message[1]

    // Set theme
    console.log(tonight)
    if (tonight) {
      const cssUrl = browser.runtime.getURL('content/css/index.css')
      const cssTag = `<link rel='stylesheet' href='${cssUrl}'>`
      document.head.innerHTML += cssTag
    }

    // Select random slogan
    console.log(`Loaded ${slogans.length} slogans`)
    let sloganText

    if (slogans.length >= 1) {
      const random = Math.floor(Math.random() * slogans.length)
      sloganText = slogans[random].toLowerCase()
      console.log(`Slogan changed to: ${sloganText}`)
    } else {
      sloganText = "welkom bij somtodayn't"
      console.log('No slogans found')
    }

    // Split the slogan into array
    const sloganArray = sloganText.split(' ')
    const slogan = {
      white: '',
      blue: ''
    }

    // Set the last word in the array to be blue
    if (sloganArray.length > 1) {
      slogan.blue = sloganArray.pop()
      for (let index = 0; index < sloganArray.length; index++) {
        slogan.white = slogan.white + sloganArray[index] + ' '
      }
    } else {
      slogan.white = sloganArray
    }

    // Edit HTML
    document.getElementById('slogan').innerHTML =
      `<span class="white block">${slogan.white}</span><span>${slogan.blue}</span>`

    // Add a little credit
    document.querySelectorAll('footer > span')[0].innerHTML = "Somtodayn't is een add-on door McArn."
  }
}

// Send request to background script
browser.runtime.sendMessage({
  type: 'get'
})

// Receive response from background script
browser.runtime.onMessage.addListener(changeSlogan)