Choosing specific pages to launch addons on

You can limit addons launch to specific pages of a website.

Important: when are addons launched

Addons are launched on every DOM load - it means, after the user navigates to a new page or reloads the current one, or navigates back/forward in history to other page, or reopens a previously closed page. In all these cases a fresh new page is loaded in the browser and every addon that fits it is relaunched on it.

After an addon is launched on the page it will not be launched again (its start function will not be called). So addons are not launched on:

• hash change - when just hash changes, page’s DOM is not reloaded; if addon was already launched on this page it remains active, so no need in injecting and launching it again.
• programmatic manipulation with history - if window.history object is modified programmatically without actual page change, previous addons also remain on the page so no need to launch them again.

So there are different approaches on managing addons for Sites that reload pages during navigation and Fully dynamic sites (usually single-page applications)

Sites that reload pages during navigation

For such sites you can use entry points to limit your addon to some specific pages and split its logic for different pages. Entry points are set as pages property in .manifest file.

Let’s look at example:

.js file:

function() {

      function tasksLogic(){
        alert('user part');
      };

      function adminLogic(){
        alert('admin part');
      };

  return {
    start: function(utils_described_later, entryPoint) {
      if (entryPoint === ‘tasks’)
            tasksLogic();
      else
            adminLogic();
    }
  };
}

.manifest file:

{
  "pages": [
    {
      "path": "^(/\w+)/tasks",
      "entryPoint": "tasks"
    },
    {
      "path": "^/admin/",
      "entryPoint": "admin"
    }
  ]
}

Entry points

Entry points are contained in object pages - there are two records with fields:

• path - a string representation of a Regexp
• entryPoint - a string name of current entryPoint

On a new page load, entryPoints are iterated in the order they are given in config:

• the first entryPoint with path that fits location.pathname is chosen as resulting entryPoint and addon is applied - it’s start function receives resulting entryPoint name as a second parameter.
• if no entryPoint fits, addon is not applied

Results:

url	addon is applied	entryPoint	alert output
somesaas.com/admin/	Yes	admin	admin part
somesaas.com/adminproject/	No	-
somesaas.com/clientproject/tasks	Yes	tasks	tasks part
somesaas.com/tasks	No	-
somesaas.com/admin/tasks	Yes	tasks	tasks part

Fully dynamic sites

For sites that you should design addons to be applied from the very beginning on any page. Then you can watch for hash change using taistApi.hash:

• taistApi.hash.onChange(callback) - runs callback(newHash, oldHash) when the hash part of the URL is changed.
• taistApi.hash.when(regexp, callback) - runs callback() every time when hash changes and fits regexp. regexp can be given as a string or a RegExp object.