source: node_modules/prismjs/plugins/copy-to-clipboard/prism-copy-to-clipboard.js

(function () {

        if (typeof Prism === 'undefined' || typeof document === 'undefined') {
                return;
        }

        if (!Prism.plugins.toolbar) {
                console.warn('Copy to Clipboard plugin loaded before Toolbar plugin.');

                return;
        }

        /**
         * When the given elements is clicked by the user, the given text will be copied to clipboard.
         *
         * @param {HTMLElement} element
         * @param {CopyInfo} copyInfo
         *
         * @typedef CopyInfo
         * @property {() => string} getText
         * @property {() => void} success
         * @property {(reason: unknown) => void} error
         */
        function registerClipboard(element, copyInfo) {
                element.addEventListener('click', function () {
                        copyTextToClipboard(copyInfo);
                });
        }

        // https://stackoverflow.com/a/30810322/7595472

        /** @param {CopyInfo} copyInfo */
        function fallbackCopyTextToClipboard(copyInfo) {
                var textArea = document.createElement('textarea');
                textArea.value = copyInfo.getText();

                // Avoid scrolling to bottom
                textArea.style.top = '0';
                textArea.style.left = '0';
                textArea.style.position = 'fixed';

                document.body.appendChild(textArea);
                textArea.focus();
                textArea.select();

                try {
                        var successful = document.execCommand('copy');
                        setTimeout(function () {
                                if (successful) {
                                        copyInfo.success();
                                } else {
                                        copyInfo.error();
                                }
                        }, 1);
                } catch (err) {
                        setTimeout(function () {
                                copyInfo.error(err);
                        }, 1);
                }

                document.body.removeChild(textArea);
        }
        /** @param {CopyInfo} copyInfo */
        function copyTextToClipboard(copyInfo) {
                if (navigator.clipboard) {
                        navigator.clipboard.writeText(copyInfo.getText()).then(copyInfo.success, function () {
                                // try the fallback in case `writeText` didn't work
                                fallbackCopyTextToClipboard(copyInfo);
                        });
                } else {
                        fallbackCopyTextToClipboard(copyInfo);
                }
        }

        /**
         * Selects the text content of the given element.
         *
         * @param {Element} element
         */
        function selectElementText(element) {
                // https://stackoverflow.com/a/20079910/7595472
                window.getSelection().selectAllChildren(element);
        }

        /**
         * Traverses up the DOM tree to find data attributes that override the default plugin settings.
         *
         * @param {Element} startElement An element to start from.
         * @returns {Settings} The plugin settings.
         * @typedef {Record<"copy" | "copy-error" | "copy-success" | "copy-timeout", string | number>} Settings
         */
        function getSettings(startElement) {
                /** @type {Settings} */
                var settings = {
                        'copy': 'Copy',
                        'copy-error': 'Press Ctrl+C to copy',
                        'copy-success': 'Copied!',
                        'copy-timeout': 5000
                };

                var prefix = 'data-prismjs-';
                for (var key in settings) {
                        var attr = prefix + key;
                        var element = startElement;
                        while (element && !element.hasAttribute(attr)) {
                                element = element.parentElement;
                        }
                        if (element) {
                                settings[key] = element.getAttribute(attr);
                        }
                }
                return settings;
        }

        Prism.plugins.toolbar.registerButton('copy-to-clipboard', function (env) {
                var element = env.element;

                var settings = getSettings(element);

                var linkCopy = document.createElement('button');
                linkCopy.className = 'copy-to-clipboard-button';
                linkCopy.setAttribute('type', 'button');
                var linkSpan = document.createElement('span');
                linkCopy.appendChild(linkSpan);

                setState('copy');

                registerClipboard(linkCopy, {
                        getText: function () {
                                return element.textContent;
                        },
                        success: function () {
                                setState('copy-success');

                                resetText();
                        },
                        error: function () {
                                setState('copy-error');

                                setTimeout(function () {
                                        selectElementText(element);
                                }, 1);

                                resetText();
                        }
                });

                return linkCopy;

                function resetText() {
                        setTimeout(function () { setState('copy'); }, settings['copy-timeout']);
                }

                /** @param {"copy" | "copy-error" | "copy-success"} state */
                function setState(state) {
                        linkSpan.textContent = settings[state];
                        linkCopy.setAttribute('data-copy-state', state);
                }
        });
}());