1.模块定义
(function () {
var modules = {};
// Stack of moduleIds currently being built.
var requireStack = [];
// Map of module ID -> index into requireStack of modules currently being built.
var inProgressModules = {};
var SEPARATOR = '.';
function build (module) {
var factory = module.factory;
var localRequire = function (id) {
var resultantId = id;
// Its a relative path, so lop off the last portion and add the id (minus "./")
if (id.charAt(0) === '.') {
resultantId = module.id.slice(0, module.id.lastIndexOf(SEPARATOR)) + SEPARATOR + id.slice(2);
}
return require(resultantId);
};
module.exports = {};
delete module.factory;
factory(localRequire, module.exports, module);
return module.exports;
}
require = function (id) {
if (!modules[id]) {
throw 'module ' + id + ' not found';
} else if (id in inProgressModules) {
var cycle = requireStack.slice(inProgressModules[id]).join('->') + '->' + id;
throw 'Cycle in require graph: ' + cycle;
}
if (modules[id].factory) {
try {
inProgressModules[id] = requireStack.length;
requireStack.push(id);
return build(modules[id]);
} finally {
delete inProgressModules[id];
requireStack.pop();
}
}
return modules[id].exports;
};
define = function (id, factory) {
if (modules[id]) {
throw 'module ' + id + ' already defined';
}
modules[id] = {
id: id,
factory: factory
};
};
define.remove = function (id) {
delete modules[id];
};
define.moduleMap = modules;
})();