backbone.assign

A micro library for creating memory conciencious Backbone views.

Reasoning

In long-lived, single page web-apps, the importance of maintaining a zero memory footprint is high. Although performing various cleanup operations,vanilla Backbone does not allow for views to easily manage the state of their sub-views. This makes it difficult to ensure that when views are destroyed they efficiently and completely cleanup all event handlers and elements they have created and delegated.

Installation

npm install backbone.assign

Usage

Backbone.assign is provided as an ES6 module;

import ParentView from "backbone.assign";

Using Backbone.assign, sub-views are assigned to a child element, and then rendered implicitly. This allows backbone.assign and the parent view to manage the state of all of it's sub-views. An example view assignment may be as follows;

const PageView = ParentView.extend({
    initialize(options) {
        // create a view
        this.listView = new ListView();
    },
    render() {
        // render and append the view
        // to the .list element
        this.assign({
            '.list': this.listView
        });
    }
});

Assumptions

In order for backbone.assign to work effectively without intervention, two asumptionns are made;

All events will be delegated from the root element of the view. This can be achieved by using the events object exclusively, or by delegating events from this.el.
The render function will not alter the view's root element.

Events

Event Name	Description
`onBeforeRender`	called immediately before the view is rendered
`onRender`	called immediately after the view is rendered
`onBeforeClose`	called immediately before the view is closed
`onClose`	called immediately after the view is closed

Additional cleanup

To perform any additional cleanup of memory an onClose method is exposed. The onClose function will be called after the onBeforeClose event, but before memory cleanup. This

Preventing final cleanup

Returning false from the onClose function will rekindle the view, preventing cleanup from being finalized.

ripjar/backbone.assign