single.js

import * as rcu from 'rcu';
import get from '../utils/get';
import load from '../load';

var promises = {},
	global = ( typeof window !== 'undefined' ? window : {} );

export default loadSingle;

// Load a single component:
//
//     Ractive.load( 'path/to/foo' ).then( function ( Foo ) {
//       var foo = new Foo(...);
//     });
function loadSingle ( path, parentUrl, baseUrl, cache ) {
	var promise, url;

	url = rcu.resolve( path, path[0] === '.' ? parentUrl : baseUrl );

	// if this component has already been requested, don't
	// request it again
	if ( !cache || !promises[ url ] ) {
		promise = get( url ).then( function ( template ) {
			return new Promise( function ( fulfil, reject ) {
				rcu.make( template, {
					url: url,
					loadImport: function ( name, path, parentUrl, callback ) {
						// if import has a relative URL, it should resolve
						// relative to this (parent). Otherwise, relative
						// to load.baseUrl
						loadSingle( path, parentUrl, baseUrl, cache ).then( callback, reject );
					},
					require: ractiveRequire
				}, fulfil, reject );
			});
		});

		promises[ url ] = promise;
	}

	return promises[ url ];
}

function ractiveRequire ( name ) {
	var dependency, qualified;

	dependency = load.modules.hasOwnProperty( name ) ? load.modules[ name ] :
	             global.hasOwnProperty( name ) ? global[ name ] : null;

	if ( !dependency && typeof require === 'function' ) {
		try {
			dependency = require( name );
		} catch (e) {
			if (typeof process !== 'undefined') {
				dependency = require( process.cwd() + '/' + name );
			} else {
				throw e;
			}
		}
	}

	if ( !dependency ) {
		qualified = !/^[$_a-zA-Z][$_a-zA-Z0-9]*$/.test( name ) ? '["' + name + '"]' : '.' + name;
		throw new Error( 'Ractive.load() error: Could not find dependency "' + name + '". It should be exposed as Ractive.load.modules' + qualified + ' or window' + qualified );
	}

	return dependency;
}