systemjs/lib/global.js
2015-05-12 13:54:05 +02:00

103 lines
3.1 KiB
JavaScript

/*
SystemJS Global Format
Supports
metadata.deps
metadata.globals
metadata.exports
Without metadata.exports, detects writes to the global object.
*/
(function() {
var __globalName = typeof window != 'undefined' ? 'window' : (typeof global != 'undefined' ? 'global' : 'self');
function readGlobalProperty(p, value) {
var pParts = p.split('.');
while (pParts.length)
value = value[pParts.shift()];
return value;
}
hook('onScriptLoad', function(onScriptLoad) {
return function(load) {
if (load.metadata.format == 'global') {
load.metadata.registered = true;
var globalValue = readGlobalProperty(load.metadata.exports, __global);
load.metadata.execute = function() {
return globalValue;
}
}
return onScriptLoad.call(this, load);
};
});
hook('fetch', function(fetch) {
return function(load) {
if (load.metadata.exports)
load.metadata.format = 'global';
// A global with exports, no globals and no deps
// can be loaded via a script tag
if (load.metadata.format == 'global'
&& load.metadata.exports && !load.metadata.globals
&& (!load.metadata.deps || load.metadata.deps.length == 0))
load.metadata.scriptLoad = true;
return fetch.call(this, load);
};
});
// ideally we could support script loading for globals, but the issue with that is that
// we can't do it with AMD support side-by-side since AMD support means defining the
// global define, and global support means not definining it, yet we don't have any hook
// into the "pre-execution" phase of a script tag being loaded to handle both cases
hook('instantiate', function(instantiate) {
return function(load) {
var loader = this;
if (!load.metadata.format)
load.metadata.format = 'global';
// global is a fallback module format
if (load.metadata.format == 'global' && !load.metadata.registered) {
load.metadata.execute = function(require, exports, module) {
var exportName = load.metadata.exports;
if (!exportName)
loader.get('@@global-helpers').prepareGlobal(module.id);
else
load.source += '\n' + __globalName + '["' + exportName + '"] = ' + exportName + ';';
// disable module detection
var define = __global.define;
var require = __global.require;
__global.define = undefined;
__global.module = undefined;
__global.exports = undefined;
// allow globals to be defined by other modules (including non globals)
if (load.metadata.globals) {
var globals = {};
for (var g in load.metadata.globals)
globals[g] = require(load.metadata.globals[g]);
}
__exec(load, globals);
__global.require = require;
__global.define = define;
if (exportName)
return readGlobalProperty(exportName, __global);
else
return loader.get('@@global-helpers').retrieveGlobal(module.id);
}
}
return instantiate.call(this, load);
};
});
})();