Share image via social media from PWA

Question

In my Nuxt PWA I have a function that converts my HTML to Canvas using this package. The generated image is in base 64. Now I want to be able to share that image via: Whatsapp, Facebook, email, Instagram etc. I have found several packages but they all don't seem to support sharing files only URLs and Text.

This is my share function:

shareTicket(index) {
  html2canvas(this.$refs['ticket-' + index][0], {
    backgroundColor: '#efefef',
    useCORS: true, // if the contents of screenshots, there are images, there may be a case of cross-domain, add this parameter, the cross-domain file to solve the problem
  }).then((canvas) => {
    let url = canvas.toDataURL('image/png') // finally produced image url

    if (navigator.share) {
      navigator.share({
        title: 'Title to be shared',
        text: 'Text to be shared',
        url: this.url,
      })
    }
  })

When I take out the if (navigator.share) condition I get an error in my console that navigator.share is not a function. I read somewhere that it only works on HTTPS so I uploaded to my staging server and tried but still got the same error.

Just to be clear I want to be able to share the generated image itself and not a URL.

Answer 1

Tell me if this URL works for you: https://nuxt-share-social-media.netlify.app
If it does, you can find the Github repo here: https://github.com/kissu/so-share-image-bounty

The code is

<template>
  <div>
    <div id="capture" ref="element" style="padding: 10px; background: #f5da55">
      <h4 style="color: #000">Hello world!</h4>
    </div>

    <br />
    <br />
    <button @click="share">share please</button>
  </div>
</template>

<script>
import html2canvas from 'html2canvas'

export default {
  methods: {
    share() {
      // iife here
      ;(async () => {
        if (!('share' in navigator)) {
          return
        }
        // `element` is the HTML element you want to share.
        // `backgroundColor` is the desired background color.
        const canvas = await html2canvas(this.$refs.element)
        canvas.toBlob(async (blob) => {
          // Even if you want to share just one file you need to
          // send them as an array of files.
          const files = [new File([blob], 'image.png', { type: blob.type })]
          const shareData = {
            text: 'Some text',
            title: 'Some title',
            files,
          }
          if (navigator.canShare(shareData)) {
            try {
              await navigator.share(shareData)
            } catch (err) {
              if (err.name !== 'AbortError') {
                console.error(err.name, err.message)
              }
            }
          } else {
            console.warn('Sharing not supported', shareData)
          }
        })
      })()
    },
  },
}
</script>

Inspired from @denvercoder9!

---

More info about the answer

• I've used an IIFE because I was not sure how the whole thing works, but it's works great in a method context!
• I've added a missing async because ESlint and in case you wanted to make something after
• I've used $refs because this is how you should select specific parts of the DOM in the Vue ecosystem
• I've striped some things to keep it simple, hosted on Netlify to have some simple HTTPS and tested it on Chrome (v91), working perfectly fine!
• Here is the link again to the MDN documentation of the Web Share API.

---

Compatibility

This is my experience for the browsers (tested on the MDN example and on my app, exact same results)

where	working
iPad chrome	yes
iPad firefox	yes
iPad safari	yes
windows chrome	yes
windows firefox	no
android chrome	yes
android firefox	no
desktop linux chrome	no
desktop linux firefox	no

For me, this was a mobile only feature (like for Android). But it looks like even some desktop browsers are handling this too. I have to admit that I was really surprised to even see this one work on Windows.
Here is an interesting post from Google that correlates this compatibility: https://web.dev/web-share/#browser-support

Reading MDN again, it says

The navigator.share() method of the Web Share API invokes the native sharing mechanism of the device.

So, I guess that the "(desktop) device" mostly do not support the Share API.

TLDR: this is working totally as intended but the compatibility is really subpar so far.

Answer 2

I have a variation of the code below in a share() function in an app of mine and it works fine if executed on the client.

const share = async() => {
  if (!('share' in navigator)) {
    return;
  }
  // `element` is the HTML element you want to share.
  // `backgroundColor` is the desired background color.
  const canvas = await html2canvas(element, {
    backgroundColor,
  });
  canvas.toBlob(async (blob) => {
    // Even if you want to share just one file you need to 
    // send them as an array of files.
    const files = [new File([blob], 'image.png', { type: blob.type })];
    const shareData = {
      text: 'Some text',
      title: 'Some title',
      files,
    };
    if (navigator.canShare(shareData)) {
      try {
        await navigator.share(shareData);
      } catch (err) {
        if (err.name !== 'AbortError') {
          console.error(err.name, err.message);      
        }
      }
    } else {
      console.warn('Sharing not supported', shareData);            
    }
  });
};