Closing tabs with a specific meta TAG in firefox-addon using javascript

Question

I have this addon which inserts the following "meta" TAG on the pages it opens.Towards the end, I want to close all the tabs with that TAG on the page header.

<meta id="CLOSE_LATER">

I have written a simple for-loop:

var TAG = "CLOSE_LATER";
var tabs = require("sdk/tabs");

for(var i=0; i<tabs.length; i++){
    var tab = tabs[i];

        console.log("****START****");
        console.log("CLOSING TAB : "+i+"of : "+tabs.length);
    searchTag(tab, TAG,i)
    .then(function success(rValue) {
        if (rValue) {
            tab.close();
            console.log("CLOSED i: "+i);                
        }
        else{
            console.log("NOT CLOSED i: "+i);
        }
    }, function failure(error) {
        console.log("Error : searchTag()");
    });
    console.log("****END****");     
}

Where searchTag() attached a script to the page "seachtag.js" to search the TAG.

searchTag() returns a promise resolved to TRUE is it find the TAG on the page and resolves to FALSE otherwise.

Example situation: I have 3 URL's of which only URL-2 and URL-3 have the TAG in their head. So only URL-2 & 3 should be closed, but only URL-3 is closed.

Below is the example log:

Answer 1

Try this:

var TAG = "CLOSE_LATER";
var tabs = require("sdk/tabs");

var success = function (rValue) {
    if (rValue) {
        this.close();
        //console.log("CLOSED i: "+i);                
    }
    else{
        //console.log("NOT CLOSED i: "+i);
    }
};

for(var i=0; i<tabs.length; i++){
    var tab = tabs[i];

        console.log("****START****");
        console.log("CLOSING TAB : "+i+"of : "+tabs.length);
    searchTag(tab, TAG,i)
    .then(success.bind(tab), function failure(error) {
        console.log("Error : searchTag()");
    });
    console.log("****END****");     
}

That binds the tab you are interested in to the this variable in the success function so that each invocation of success will have the correct tab object to work with.

Note that I commented out the logging because you no longer have access to i but if you want that to work again you'll just have to encapsulate tab and i in a new object for each loop iteration and bind that instead.

I've not used this trick inside a promise before so it's possible the promise resolution will do something to break the binding but hopefully not.