创建一个全局变量chrome app

Question

I am creating a Chrome app. this is my manifest file.

{
//...... description and other things
//.......
"app": {
    "background": {
        "scripts": ["js/main.js"]
    }
},
// other things

}

and in my js/main.js file, I have defined a global variable as globalData.

    chrome.app.runtime.onLaunched.addListener(function() {

  chrome.app.window.create('/dashboard.html', {
    'bounds': {
      'width': screen.availWidth,
      'height': screen.availHeight
    }
  });
});
var globalData;

(purpose of doing that I need a variable that available whole runtime). In dashboar.html I have included services.js files. Is there a way that I can use that globalData variable in services.js.

Answer 1

From any chrome app window you can access the backgroundPage, and thus also access variables assigned to its global object (top level var like you have are automatically attached)

Try this:

chrome.runtime.getBackgroundPage(function(bgpage) {
  console.log(bgpage.globalData);
})

You can also save a reference to the background page, or save a reference to the global data object itself (usual javascript caveats apply):

// in bgpage
var globalData = {};
globalData.apples = ['red', 'green'];

// in app window
var globalData;
chrome.runtime.getBackgroundPage(function(bgpage) {
   globalData = bgpage.globalData;
   main();
})
function main() {
   console.log(globalData.apples);
}