README.md

Chart.Deferred.js

A Chart.js plugin to defer the initial chart update until the user scrolls and the canvas appears inside the viewport. The main intent of Chart.Deferred.js is to trigger the initial chart animations when the user is likely to see them.

Requires Chart.js 2.1.5 or later.

Usage

You can download the latest version of Chart.Deferred.js on GitHub

Configuration

To configure this plugin, you can simply add the following entries to your chart options:

Name	Type	Default	Description
deferred	Object/Boolean	true	The deferred options (see deferred.* options). Also accepts a boolean, in which case if true, the chart will be deferred using the default options, else if false, the chart will not be deferred.
deferred.enabled	Boolean	true	true to enable this plugin, else false to disable it for the associated chart.
deferred.xOffset	Number/String	0	Number of pixels (or percent of the canvas width) from which the chart is considered inside the viewport.
deferred.yOffset	Number/String	0	Number of pixels (or percent of the canvas height) from which the chart is considered inside the viewport.
deferred.delay	Number	0	Number of milliseconds to delay the loading after the chart is considered inside the viewport.

For example:

{
    deferred: {           // enabled by default
        xOffset: 150,     // defer until 150px of the canvas width are inside the viewport
        yOffset: '50%',   // defer until 50% of the canvas height are inside the viewport
        delay: 500        // delay of 500 ms after the canvas is considered inside the viewport
    }
}

Note that default options will defer the chart loading until the first line of pixels of the canvas appears in the viewport.

Development

You first need to install node dependencies (requires Node.js):

> npm install

The following commands will then be available from the repository root:

> gulp build            // build dist files
> gulp build --watch    // build and watch for changes
> gulp lint             // perform code linting
> gulp package          // create an archive with dist files and samples

License

Chart.Deferred.js is available under the MIT license.