systemjs
Version:
Dynamic ES module loader
192 lines (174 loc) • 7.51 kB
JavaScript
(function () {
var hasDocument = typeof document !== 'undefined';
var baseUrl;
if (hasDocument) {
var baseEl = document.querySelector('base[href]');
if (baseEl)
baseUrl = baseEl.href;
}
if (!baseUrl && typeof location !== 'undefined') {
baseUrl = location.href.split('#')[0].split('?')[0];
var lastSepIndex = baseUrl.lastIndexOf('/');
if (lastSepIndex !== -1)
baseUrl = baseUrl.slice(0, lastSepIndex + 1);
}
var backslashRegEx = /\\/g;
function resolveIfNotPlainOrUrl (relUrl, parentUrl) {
if (relUrl.indexOf('\\') !== -1)
relUrl = relUrl.replace(backslashRegEx, '/');
// protocol-relative
if (relUrl[0] === '/' && relUrl[1] === '/') {
return parentUrl.slice(0, parentUrl.indexOf(':') + 1) + relUrl;
}
// relative-url
else if (relUrl[0] === '.' && (relUrl[1] === '/' || relUrl[1] === '.' && (relUrl[2] === '/' || relUrl.length === 2 && (relUrl += '/')) ||
relUrl.length === 1 && (relUrl += '/')) ||
relUrl[0] === '/') {
var parentProtocol = parentUrl.slice(0, parentUrl.indexOf(':') + 1);
// Disabled, but these cases will give inconsistent results for deep backtracking
//if (parentUrl[parentProtocol.length] !== '/')
// throw Error('Cannot resolve');
// read pathname from parent URL
// pathname taken to be part after leading "/"
var pathname;
if (parentUrl[parentProtocol.length + 1] === '/') {
// resolving to a :// so we need to read out the auth and host
if (parentProtocol !== 'file:') {
pathname = parentUrl.slice(parentProtocol.length + 2);
pathname = pathname.slice(pathname.indexOf('/') + 1);
}
else {
pathname = parentUrl.slice(8);
}
}
else {
// resolving to :/ so pathname is the /... part
pathname = parentUrl.slice(parentProtocol.length + (parentUrl[parentProtocol.length] === '/'));
}
if (relUrl[0] === '/')
return parentUrl.slice(0, parentUrl.length - pathname.length - 1) + relUrl;
// join together and split for removal of .. and . segments
// looping the string instead of anything fancy for perf reasons
// '../../../../../z' resolved to 'x/y' is just 'z'
var segmented = pathname.slice(0, pathname.lastIndexOf('/') + 1) + relUrl;
var output = [];
var segmentIndex = -1;
for (var i = 0; i < segmented.length; i++) {
// busy reading a segment - only terminate on '/'
if (segmentIndex !== -1) {
if (segmented[i] === '/') {
output.push(segmented.slice(segmentIndex, i + 1));
segmentIndex = -1;
}
}
// new segment - check if it is relative
else if (segmented[i] === '.') {
// ../ segment
if (segmented[i + 1] === '.' && (segmented[i + 2] === '/' || i + 2 === segmented.length)) {
output.pop();
i += 2;
}
// ./ segment
else if (segmented[i + 1] === '/' || i + 1 === segmented.length) {
i += 1;
}
else {
// the start of a new segment as below
segmentIndex = i;
}
}
// it is the start of a new segment
else {
segmentIndex = i;
}
}
// finish reading out the last segment
if (segmentIndex !== -1)
output.push(segmented.slice(segmentIndex));
return parentUrl.slice(0, parentUrl.length - pathname.length) + output.join('');
}
}
/*
* Import maps implementation
*
* To make lookups fast we pre-resolve the entire import map
* and then match based on backtracked hash lookups
*
*/
function resolveUrl (relUrl, parentUrl) {
return resolveIfNotPlainOrUrl(relUrl, parentUrl) || (relUrl.indexOf(':') !== -1 ? relUrl : resolveIfNotPlainOrUrl('./' + relUrl, parentUrl));
}
/*
* Loads JSON, CSS, Wasm module types based on file extension
* filters and content type verifications
*/
(function(global) {
var systemJSPrototype = global.System.constructor.prototype;
var moduleTypesRegEx = /^[^#?]+\.(css|html|json|wasm)([?#].*)?$/;
var _shouldFetch = systemJSPrototype.shouldFetch.bind(systemJSPrototype);
systemJSPrototype.shouldFetch = function (url) {
return _shouldFetch(url) || moduleTypesRegEx.test(url);
};
var jsonContentType = /^application\/json(;|$)/;
var cssContentType = /^text\/css(;|$)/;
var wasmContentType = /^application\/wasm(;|$)/;
var fetch = systemJSPrototype.fetch;
systemJSPrototype.fetch = function (url, options) {
return fetch(url, options)
.then(function (res) {
if (options.passThrough)
return res;
if (!res.ok)
return res;
var contentType = res.headers.get('content-type');
if (jsonContentType.test(contentType))
return res.json()
.then(function (json) {
return new Response(new Blob([
'System.register([],function(e){return{execute:function(){e("default",' + JSON.stringify(json) + ')}}})'
], {
type: 'application/javascript'
}));
});
if (cssContentType.test(contentType))
return res.text()
.then(function (source) {
source = source.replace(/url\(\s*(?:(["'])((?:\\.|[^\n\\"'])+)\1|((?:\\.|[^\s,"'()\\])+))\s*\)/g, function (match, quotes, relUrl1, relUrl2) {
return ['url(', quotes, resolveUrl(relUrl1 || relUrl2, url), quotes, ')'].join('');
});
return new Response(new Blob([
'System.register([],function(e){return{execute:function(){var s=new CSSStyleSheet();s.replaceSync(' + JSON.stringify(source) + ');e("default",s)}}})'
], {
type: 'application/javascript'
}));
});
if (wasmContentType.test(contentType))
return (WebAssembly.compileStreaming ? WebAssembly.compileStreaming(res) : res.arrayBuffer().then(WebAssembly.compile))
.then(function (module) {
if (!global.System.wasmModules)
global.System.wasmModules = Object.create(null);
global.System.wasmModules[url] = module;
// we can only set imports if supported (eg early Safari doesnt support)
var deps = [];
var setterSources = [];
if (WebAssembly.Module.imports)
WebAssembly.Module.imports(module).forEach(function (impt) {
var key = JSON.stringify(impt.module);
if (deps.indexOf(key) === -1) {
deps.push(key);
setterSources.push('function(m){i[' + key + ']=m}');
}
});
return new Response(new Blob([
'System.register([' + deps.join(',') + '],function(e){var i={};return{setters:[' + setterSources.join(',') +
'],execute:function(){return WebAssembly.instantiate(System.wasmModules[' + JSON.stringify(url) +
'],i).then(function(m){e(m.exports)})}}})'
], {
type: 'application/javascript'
}));
});
return res;
});
};
})(typeof self !== 'undefined' ? self : global);
})();