clipboard.ts

// https://stackoverflow.com/questions/400212/how-do-i-copy-to-the-clipboard-in-javascript
export function copyTextToClipboard(text: string) {
    const textArea = document.createElement("textarea");

    //
    // *** This styling is an extra step which is likely not required. ***
    //
    // Why is it here? To ensure:
    // 1. the element is able to have focus and selection.
    // 2. if element was to flash render it has minimal visual impact.
    // 3. less flakyness with selection and copying which **might** occur if
    //    the textarea element is not visible.
    //
    // The likelihood is the element won't even render, not even a
    // flash, so some of these are just precautions. However in
    // Internet Explorer the element is visible whilst the popup
    // box asking the user for permission for the web page to
    // copy to the clipboard.
    //

    // Place in top-left corner of screen regardless of scroll position.
    textArea.style.position = 'fixed';
    textArea.style.top = '0';
    textArea.style.left = '0';

    // Ensure it has a small width and height. Setting to 1px / 1em
    // doesn't work as this gives a negative w/h on some browsers.
    textArea.style.width = '2em';
    textArea.style.height = '2em';

    // We don't need padding, reducing the size if it does flash render.
    textArea.style.padding = '0';

    // Clean up any borders.
    textArea.style.border = 'none';
    textArea.style.outline = 'none';
    textArea.style.boxShadow = 'none';

    // Avoid flash of white box if rendered for any reason.
    textArea.style.background = 'transparent';

    textArea.value = text;

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

    try {
        const successful = document.execCommand('copy');
        const msg = successful ? 'successful' : 'unsuccessful';
        console.log('Copying text command was ' + msg);
    } catch (err) {
        console.log('Oops, unable to copy');
    }

    document.body.removeChild(textArea);
}