Clipboard.js: Replace event emitter with promises

[zenorocha]

Part I of a new major release proposal #516

Current state

var clipboard = new Clipboard('.btn');

clipboard.on('success', function(e) {
  // it worked
});

clipboard.on('error', function(e) {
  // it didn't work
});

Proposal

clipboard.copy('.btn')
  .then(function(e) {
    // it worked
  })
  .catch(function(e) {
    // it didn't work
  })

Benefits

This change will make the API more modern, remove tiny-emitter dependency, and help those who need to make actions before copying (for example, make an ajax request).

Drawbacks

This change will drop support for IE: https://caniuse.com/#search=promises

Related

152 #336 #338 #361 #492

[vinhboy]

Can you use bluebirdjs, or a polyfill to continue IE support?

[ClementParis016]

@vinhboy I think it would be better to advise people to include a promise polyfill separately if they need it

[zenorocha]

I agree with @ClementParis016, if we add a polyfill by default the bundle will be huge. We'll probably advise people to include themselves.

[vidhill]

I'm a little confused, am I?
a Promise is only ever resolve once..

So with this implementation if a user clicks on the button multiple times you would only ever catch the first click event?

[bblack]

This change will make the API more modern

I'm also confused, for the same reason as @vidhill. Promises are not just "modern" replacements for events.

and help those who need to make actions before copying (for example, make an ajax request)

Is this not already possible?