how to use modernizr to load ractive legacy - modernizr

Question

I need to work on a project, that needs legacy support.
How would I go about integrating it with modernizr to only load legacy if necessary?
Is that even possible?

Answer 1

The legacy build includes polyfills for a few bits and pieces that aren't in IE8 - Ractive does its own check when it first loads, and throws an error if it detects missing features (and it's the non-legacy build). The detection code is here - so you could just copy that into your app:
function useRactiveLegacy () {
return (
typeof Date.now !== FUNCTION ||
typeof String.prototype.trim !== FUNCTION ||
typeof Object.keys !== FUNCTION ||
typeof Array.prototype.indexOf !== FUNCTION ||
typeof Array.prototype.forEach !== FUNCTION ||
typeof Array.prototype.map !== FUNCTION ||
typeof Array.prototype.filter !== FUNCTION ||
( typeof window !== 'undefined' && typeof window.addEventListener !== FUNCTION )
);
}
// using Modernizr
Modernizr.load({
test: !useRactiveLegacy(),
yep: 'ractive.js',
nope: 'ractive-legacy.js
});
// using AMD
require([ useRactiveLegacy() ? 'ractive-legacy' : 'ractive' ], function ( Ractive ) {
/* code goes here */
});
Bear in mind that these checks could change with future versions of Ractive - for example, there may come a time when we decide to relegate Promises to the legacy version, rather than automatically polyfilling it.