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HTML Settings

Here you can Sed posuere consectetur est at lobortis. Donec ullamcorper nulla non metus auctor fringilla. Maecenas sed diam eget risus varius blandit sit amet non magna. Donec id elit non mi porta gravida at eget metus. Praesent commodo cursus magna, vel scelerisque nisl consectetur et.

            
              const hashstr = s => {
  let hash = 0;
  if (s.length == 0) return hash;
  for (let i = 0; i < s.length; i++) {
    let char = s.charCodeAt(i);
    hash = ((hash << 5) - hash) + char;
    hash = hash & hash; // Convert to 32bit integer
  }
  return hash;
}

const cachedFetch = (url, options) => {
  let expiry = 5 * 60 // 5 min default
  if (typeof options === 'number') {
    expiry = options
    options = undefined
  } else if (typeof options === 'object') {
    // I hope you didn't set it to 0 seconds
    expiry = options.seconds || expiry
  }
  // Use the URL as the cache key to sessionStorage
  let cacheKey = hashstr(url)
  let cached = localStorage.getItem(cacheKey)
  let whenCached = localStorage.getItem(cacheKey + ':ts')
  if (cached !== null && whenCached !== null) {
    // it was in sessionStorage! Yay!
    // Even though 'whenCached' is a string, this operation
    // works because the minus sign tries to convert the
    // string to an integer and it will work.
    let age = (Date.now() - whenCached) / 1000
    if (age < expiry) {
      let response = new Response(new Blob([cached]))
      return Promise.resolve(response)
    } else {
      // We need to clean up this old key
      localStorage.removeItem(cacheKey)
      localStorage.removeItem(cacheKey + ':ts')
    }
  }

  return fetch(url, options).then(response => {
    // let's only store in cache if the content-type is 
    // JSON or something non-binary
    if (response.status === 200) {
      let ct = response.headers.get('Content-Type')
      if (ct && (ct.match(/application\/json/i) || ct.match(/text\//i))) {
        // There is a .json() instead of .text() but 
        // we're going to store it in sessionStorage as 
        // string anyway.
        // If we don't clone the response, it will be 
        // consumed by the time it's returned. This 
        // way we're being un-intrusive. 
        response.clone().text().then(content => {
          localStorage.setItem(cacheKey, content)
          localStorage.setItem(cacheKey + ':ts', Date.now())
        })
      }
    }
    return response
  })
}

// Default 5 min
cachedFetch('https://httpbin.org/get')
  .then(r => r.json())
  .then(info => {
    console.log('Your origin is ' + info.origin)
  })

// 2 minutes
cachedFetch('http://httpbin.org/gzip', 2 * 60)
  .then(r => r.json())
  .then(info => {
    console.log('Your origin (with gzip) is ' + info.origin)
  })

// 1 minute
cachedFetch('http://httpbin.org/ip', {
    seconds: 60
  })
  .then(r => r.json())
  .then(info => {
    console.log('Your origin (by ip only) is ' + info.origin)
  })

// cachedFetch('https://httpbin.org/html')
// .then(r => r.text())
// .then(document => {
//   console.log('Document has ' + document.match(/<p>/).length + ' paragraphs')
// })

// cachedFetch('https://httpbin.org/image/png')
// .then(r => r.blob())
// .then(image => {
//   console.log('Image is ' + image.size + ' bytes')
// })
            
          
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