Allow component config set via data attributes to be passed when initialising the component in JavaScript

[36degrees]

What

We have a few components that be configured using data attributes set at the component level (on the same HTML element that has the data-module attribute). This includes:

• button (data-prevent-double-click)
• character count (data-maxwords, data-maxlength and data-threshold)
• error summary (data-disable-auto-focus)
• notification banner (data-disable-auto-focus)

Update these components so that the same config can be set via config at the point of initialisation, for example:

var button = new Button($button).init({
  preventDoubleClick: true
})

This does not cover data attributes are used on elements ‘within’ a component, like the data-behaviour attribute used on individual checkboxes within the checkboxes component.

Relies on #2698.

Why

This aligns the general concept of 'component config' with the approach we're using for internationalisation.

Who needs to work on this

Developers

Who needs to review this

Developers

Done when

• Allow for booleans and numbers to be passed via data attributes #2832
• Allow button config set via data attributes to be passed when initialising the component in JavaScript #2836
• Allow character count config set via data attributes to be passed when initialising the component in JavaScript #2837
• Allow error summary config set via data attributes to be passed when initialising the component in JavaScript #2838
• Allow notification banner config set via data attributes to be passed when initialising the component in JavaScript #2839

[36degrees]

I think this is done 🎉