Copy to Clipboard Directive

November 14, 2015

no comments

Yesterday I was requested to create a “copy to clipboard” behavior in an AngularJS application I’m building. The main idea was to mark some content which has a meaning and to enable the user to copy the “meaning” to the clipboard by pressing a button.
Here is the directive I ended up with:

(function () {
    'use strict';
    angular.
        module("demo").
        directive("copyToClipboard", copyClipboardDirective);
 
    function copyClipboardDirective() {
        var clip;
 
        function link(scope, element) {
            function clipboardSimulator() {
                var self = this,
                    textarea,
                    container;
 
                function createTextarea() {
                    if (!self.textarea) {
                        container = document.createElement('div');
                        container.id = 'simulate-clipboard-container';
                        container.setAttribute('style', ['position: fixed;', 'left: 0px;', 'top: 0px;', 'width: 0px;', 'height: 0px;', 'z-index: 100;', 'opacity: 0;', 'display: block;'].join(''));
                        document.body.appendChild(container);
 
                        textarea = document.createElement('textarea');
                        textarea.setAttribute('style', ['width: 1px;', 'height: 1px;', 'padding: 0px;'].join(''));
                        textarea.id = 'simulate-clipboard';
                        self.textarea = textarea;
                        container.appendChild(textarea);
                    }
                }
 
                createTextarea();
            }
 
            clipboardSimulator.prototype.copy = function() {
                this.textarea.innerHTML = '';
                this.textarea.appendChild(document.createTextNode(scope.textToCopy));
                this.textarea.focus();
                this.textarea.select();
                setTimeout(function() {
                    document.execCommand('copy');
                }, 20);
            };
 
            clip = new clipboardSimulator();
 
            element[0].addEventListener('click', function() {
                clip.copy();
            });
        }
 
        return {
            restrict: 'A',
            link: link,
            scope: {
                textToCopy: '='
            }
        };
    }
}());

The main idea is borrowed from a Stack Overflow answer – How does Trello access the user’s clipboard?
I use a invisible element container to wrap a textarea which will hold the content to copy. The directive model, textToCopy, is used to get the text that I copy which means that all the directive user needs to do is to hold in that model the text he wants to copy. Once the button is clicked, I put the textToCopy data in the textarea, call the textarea select function and use the document.execCommand(‘copy’) call to force the browser to copy the selected content.

Here is how you use the directive:

<button copy-to-clipboard text-to-copy="vm.someText">Copy to Clipboard</button>

someText will be a property of the vm object which will hold the text you want to copy (in my application vm is a controller that is used with the controllerAs property).

I hope you’ll find this post useful.

Add comment
facebook linkedin twitter email

Leave a Reply

Your email address will not be published.

You may use these HTML tags and attributes: <a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <s> <strike> <strong>

*