systemjs/lib/extension-core.js
2014-07-29 18:10:26 -07:00

141 lines
3.7 KiB
JavaScript

/*
* SystemJS Core
* Code should be vaguely readable
*
*/
function core(loader) {
/*
__useDefault
When a module object looks like:
newModule({
__useDefault: true,
default: 'some-module'
})
Then importing that module provides the 'some-module'
result directly instead of the full module.
Useful for eg module.exports = function() {}
*/
var loaderImport = loader['import'];
loader['import'] = function(name, options) {
return loaderImport.call(this, name, options).then(function(module) {
return module.__useDefault ? module['default'] : module;
});
}
// support the empty module, as a concept
loader.set('@empty', loader.newModule({}));
/*
Config
Extends config merging one deep only
loader.config({
some: 'random',
config: 'here',
deep: {
config: { too: 'too' }
}
});
<=>
loader.some = 'random';
loader.config = 'here'
loader.deep = loader.deep || {};
loader.deep.config = { too: 'too' };
*/
loader.config = function(cfg) {
for (var c in cfg) {
var v = cfg[c];
if (typeof v == 'object' && !(v instanceof Array)) {
this[c] = this[c] || {};
for (var p in v)
this[c][p] = v[p];
}
else
this[c] = v;
}
}
// override locate to allow baseURL to be document-relative
var baseURI;
if (typeof window == 'undefined') {
baseURI = process.cwd() + '/';
}
else {
baseURI = document.baseURI;
if (!baseURI) {
var bases = document.getElementsByTagName('base');
baseURI = bases[0] && bases[0].href || window.location.href;
}
}
var loaderLocate = loader.locate;
var normalizedBaseURL;
loader.locate = function(load) {
if (this.baseURL != normalizedBaseURL) {
normalizedBaseURL = toAbsoluteURL(baseURI, this.baseURL);
if (normalizedBaseURL.substr(normalizedBaseURL.length - 1, 1) != '/')
normalizedBaseURL += '/';
this.baseURL = normalizedBaseURL;
}
return Promise.resolve(loaderLocate.call(this, load));
}
// Traceur conveniences
var aliasRegEx = /^\s*export\s*\*\s*from\s*(?:'([^']+)'|"([^"]+)")/;
var es6RegEx = /(?:^\s*|[}{\(\);,\n]\s*)(import\s+['"]|(import|module)\s+[^"'\(\)\n;]+\s+from\s+['"]|export\s+(\*|\{|default|function|var|const|let|[_$a-zA-Z\xA0-\uFFFF][_$a-zA-Z0-9\xA0-\uFFFF]*))/;
var loaderTranslate = loader.translate;
loader.translate = function(load) {
var loader = this;
if (load.name == '@traceur')
return loaderTranslate.call(loader, load);
// support ES6 alias modules ("export * from 'module';") without needing Traceur
var match;
if ((load.metadata.format == 'es6' || !load.metadata.format) && (match = load.source.match(aliasRegEx))) {
load.metadata.format = 'cjs';
load.source = 'module.exports = require("' + (match[1] || match[2]) + '");\n';
}
// detect ES6
else if (load.metadata.format == 'es6' || !load.metadata.format && load.source.match(es6RegEx)) {
load.metadata.format = 'es6';
// dynamically load Traceur for ES6 if necessary
if (!loader.global.traceur) {
return loader['import']('@traceur').then(function() {
return loaderTranslate.call(loader, load);
});
}
}
return loaderTranslate.call(loader, load);
}
// always load Traceur as a global
var loaderInstantiate = loader.instantiate;
loader.instantiate = function(load) {
var loader = this;
if (load.name == '@traceur') {
loader.__exec(load);
return {
deps: [],
execute: function() {
return loader.newModule({});
}
};
}
return loaderInstantiate.call(loader, load);
}
}