index.js

'use strict';

var deselectCurrent = require('toggle-selection');

var defaultMessage = 'Copy to clipboard: #{key}, Enter';

function format(message) {
  var copyKey = (/mac os x/i.test(navigator.userAgent) ? '⌘' : 'Ctrl') + '+C';
  return message.replace(/#{\s*key\s*}/g, copyKey);
}

function copy(text, options) {
  var debug, message, reselectPrevious, range, selection, mark, success = false;
  if (!options) { options = {}; }
  debug = options.debug || false;
  try {
    reselectPrevious = deselectCurrent();

    range = document.createRange();
    selection = document.getSelection();

    mark = document.createElement('span');
    mark.textContent = text;
    // reset user styles for span element
    mark.style.all = 'unset';
    // prevents scrolling to the end of the page
    mark.style.position = 'fixed';
    mark.style.top = 0;
    mark.style.clip = 'rect(0, 0, 0, 0)';
    // used to preserve spaces and line breaks
    mark.style.whiteSpace = 'pre';
    // do not inherit user-select (it may be `none`)
    mark.style.webkitUserSelect = 'text';
    mark.style.MozUserSelect = 'text';
    mark.style.msUserSelect = 'text';
    mark.style.userSelect = 'text';

    document.body.appendChild(mark);

    range.selectNode(mark);
    selection.addRange(range);

    var successful = document.execCommand('copy');
    if (!successful) {
      throw new Error('copy command was unsuccessful');
    }
    success = true;
  } catch (err) {
    debug && console.error('unable to copy using execCommand: ', err);
    debug && console.warn('trying IE specific stuff');
    try {
      window.clipboardData.setData('text', text);
      success = true;
    } catch (err) {
      debug && console.error('unable to copy using clipboardData: ', err);
      debug && console.error('falling back to prompt');
      message = format('message' in options ? options.message : defaultMessage);
      window.prompt(message, text);
    }
  } finally {
    if (selection) {
      if (typeof selection.removeRange == 'function') {
        selection.removeRange(range);
      } else {
        selection.removeAllRanges();
      }
    }

    if (mark) {
      document.body.removeChild(mark);
    }
    reselectPrevious();
  }

  return success;
}

module.exports = copy;