dalgard

function extend(target) {
  // Run through rest parameters
  Array.prototype.slice.call(arguments, 1).forEach(function (source) {
    if (source) {
      // If source is an array, only copy enumerable properties
      var keys = (Array.isArray(source) ? Object.keys(source) : Object.getOwnPropertyNames(source));

      // Iterate over keys
      keys.forEach(function (key) {
        // Standards-compliant awesomeness

dalgard

// Get the current active tab
chrome.tabs.query({ active: true, currentWindow: true }, function (tabs) {
  // Send message to check whether the script has already been injected
  chrome.tabs.sendMessage(tabs[0].id, "ping", function (response) {
    // If no message handler exists (i.e. content-script hasn't been injected before),
    // this callback is called right away with no arguments, so ...
    if (typeof response === "undefined") {
      // ... inject content-script (null means current active tab)
      chrome.tabs.executeScript(null, { file: "content_script.js" });
    }

dalgard

/*
  Set position like margin/padding shorthand - rules with null value
  are removed from output (standard)

  Example:
    @include position(0 20px null, fixed);

  Output:
    position: fixed;
    top: 0;