How to share files

Palances Liao

The modern way

Using the Web Share API's `share()` method

To share files, call navigator.share(). Note that you should always check if files can be shared with navigator.canShare() and make sure your site is using HTTPS before calling the share() method.

// Assume `blob` is a PNG image file.
const data = {
  files: [
    new File([blob], 'image.png', {
      type: blob.type,
    }),
  ],
  title: 'My title',
  text: 'My text',
};
if (navigator.canShare(data)) {
  await navigator.share(data);
}

Browser Support

Source

The classic way

The next best thing to offer to the user if the Web Share API is not supported is falling back to letting the user download the file, so they can share it manually, for example, via email or via a messenger or online social network app.

Browser Support

Source

Progressive enhancement

The method below uses the Web Share API when the browser supports it and when the data can be shared based on the supported file types. Else, it falls back to downloading the file.

const button = document.querySelector('button');
const img =  document.querySelector('img');

// Feature detection
const webShareSupported = 'canShare' in navigator;
// Update the button action text.
button.textContent = webShareSupported ? 'Share' : 'Download';

const shareOrDownload = async (blob, fileName, title, text) => {
  // Using the Web Share API.
  if (webShareSupported) {
    const data = {
      files: [
        new File([blob], fileName, {
          type: blob.type,
        }),
      ],
      title,
      text,
    };
    if (navigator.canShare(data)) {
      try {
        await navigator.share(data);
      } catch (err) {
        if (err.name !== 'AbortError') {
          console.error(err.name, err.message);
        }
      } finally {
        return;
      }
    }
  }
  // Fallback implementation.
  const a = document.createElement('a');
  a.download = fileName;
  a.style.display = 'none';
  a.href = URL.createObjectURL(blob);
  a.addEventListener('click', () => {
    setTimeout(() => {
      URL.revokeObjectURL(a.href);
      a.remove();
    }, 1000)
  });
  document.body.append(a);
  a.click();
};

button.addEventListener('click', async () => {
  const blob = await fetch(img.src).then(res => res.blob());
  await shareOrDownload(blob, 'cat.png', 'Cat in the snow', 'Getting cold feet…');
});

Demo

HTML

<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="utf-8" />
    <meta name="viewport" content="width=device-width, initial-scale=1" />
    <link
      rel="icon"
      href="data:image/svg+xml,<svg xmlns=%22http://www.w3.org/2000/svg%22 viewBox=%220 0 100 100%22><text y=%22.9em%22 font-size=%2290%22>🎉</text></svg>"
    />
    <title></title>
    <link rel="stylesheet" href="style.css" />
    <!-- TODO: Devsite - Removed inline handlers -->
    <!-- <script src="script.js" type="module"></script> -->
  </head>
  <body>
    <h1>Share a file</h1>
    <img
      width="200"
      height="200"
      alt="A cat walking in the snow."
      src="cat.png"
    />
    <button type=button></button>
  </body>
</html>

CSS


        :root {
  color-scheme: dark light;
}

html {
  box-sizing: border-box;
}

*,
*:before,
*:after {
  box-sizing: inherit;
}

body {
  margin: 1rem;
  font-family: system-ui, sans-serif;
}

img,
video {
  height: auto;
  max-width: 100%;
  display: block;
}

button {
  margin: 1rem;
}

JS


        const button = document.querySelector('button');
const img =  document.querySelector('img');

const webShareSupported = 'canShare' in navigator;
button.textContent = webShareSupported ? 'Share' : 'Download';

const shareOrDownload = async (blob, fileName, title, text) => {
  if (webShareSupported) {
    const data = {
      files: [
        new File([blob], fileName, {
          type: blob.type,
        }),
      ],
      title,
      text,
    };
    if (navigator.canShare(data)) {
      try {
        await navigator.share(data);
      } catch (err) {
        if (err.name !== 'AbortError') {
          console.error(err.name, err.message);
        }
      } finally {
        return;
      }
    }
  }
  // Fallback
  const a = document.createElement('a');
  a.download = fileName;
  a.style.display = 'none';
  a.href = URL.createObjectURL(blob);
  a.addEventListener('click', () => {
    setTimeout(() => {
      URL.revokeObjectURL(a.href);
      a.remove();
    }, 1000)
  });
  document.body.append(a);
  a.click();
};

button.addEventListener('click', async () => {
  const blob = await fetch(img.src).then(res => res.blob());
  await shareOrDownload(blob, 'cat.png', 'Cat in the snow', 'Getting cold feet…');
});