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kykyev/di.js

Last active January 4, 2016 13:58
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Extracted out angular.js dependency injection.
Raw
di.js
(function() {
var FN_ARGS = /^function\s*[^\(]*\(\s*([^\)]*)\)/m;
var FN_ARG_SPLIT = /,/;
var FN_ARG = /^\s*(_?)(\S+?)\1\s*$/;
var STRIP_COMMENTS = /((\/\/.*$)|(\/\*[\s\S]*?\*\/))/mg;
function annotate(fn) {
var $inject,
fnText,
argDecl,
last;
if (typeof fn == 'function') {
if (!($inject = fn.$inject)) {
$inject = [];
if (fn.length) {
fnText = fn.toString().replace(STRIP_COMMENTS, '');
argDecl = fnText.match(FN_ARGS);
forEach(argDecl[1].split(FN_ARG_SPLIT), function(arg){
arg.replace(FN_ARG, function(all, underscore, name){
$inject.push(name);
});
});
}
fn.$inject = $inject;
}
} else if (isArray(fn)) {
last = fn.length - 1;
assertArgFn(fn[last], 'fn');
$inject = fn.slice(0, last);
} else {
assertArgFn(fn, 'fn', true);
}
return $inject;
}
function assertNotHasOwnProperty(name, context) {
if (name === 'hasOwnProperty') {
throw new Error("hasOwnProperty is not a valid name");
}
}
function isObject(value){
return value != null && typeof value === 'object';
}
function isFunction(value){
return typeof value === 'function';
}
function isArray(value) {
return toString.call(value) === '[object Array]';
}
function reverseParams(iteratorFn) {
return function(value, key) { iteratorFn(key, value); };
}
function forEach(obj, iterator, context) {
var key;
if (obj) {
if (isFunction(obj)){
for (key in obj) {
// Need to check if hasOwnProperty exists,
// as on IE8 the result of querySelectorAll is an object without a hasOwnProperty function
if (key != 'prototype' && key != 'length' && key != 'name' && (!obj.hasOwnProperty || obj.hasOwnProperty(key))) {
iterator.call(context, obj[key], key);
}
}
} else if (obj.forEach && obj.forEach !== forEach) {
obj.forEach(iterator, context);
} else if (isArrayLike(obj)) {
for (key = 0; key < obj.length; key++)
iterator.call(context, obj[key], key);
} else {
for (key in obj) {
if (obj.hasOwnProperty(key)) {
iterator.call(context, obj[key], key);
}
}
}
}
return obj;
}
function createInjector() {
var INSTANTIATING = {},
providerSuffix = 'Provider',
path = [],
providerCache = {
$provide: {
provider: supportObject(provider),
factory: supportObject(factory),
service: supportObject(service),
value: supportObject(value),
constant: supportObject(constant),
decorator: decorator
}
},
providerInjector = (providerCache.$injector =
createInternalInjector(providerCache, function() {
throw new Error("Unknown provider: " + path.join(' <- '));
})),
instanceCache = {},
instanceInjector = (instanceCache.$injector =
createInternalInjector(instanceCache, function(servicename) {
var provider = providerInjector.get(servicename + providerSuffix);
return instanceInjector.invoke(provider.$get, provider);
}));
return {
sInjector: instanceInjector,
pInjector: providerInjector
};
////////////////////////////////////
// $provider
////////////////////////////////////
function supportObject(delegate) {
return function(key, value) {
if (isObject(key)) {
forEach(key, reverseParams(delegate));
} else {
return delegate(key, value);
}
};
}
function provider(name, provider_) {
assertNotHasOwnProperty(name, 'service');
if (isFunction(provider_) || isArray(provider_)) {
provider_ = providerInjector.instantiate(provider_);
}
if (!provider_.$get) {
throw new Error("Provider must define $get factory method.");
}
return providerCache[name + providerSuffix] = provider_;
}
function factory(name, factoryFn) { return provider(name, { $get: factoryFn }); }
function service(name, constructor) {
return factory(name, ['$injector', function($injector) {
return $injector.instantiate(constructor);
}]);
}
function value(name, val) { return factory(name, valueFn(val)); }
function constant(name, value) {
assertNotHasOwnProperty(name, 'constant');
providerCache[name] = value;
instanceCache[name] = value;
}
function decorator(serviceName, decorFn) {
var origProvider = providerInjector.get(serviceName + providerSuffix),
orig$get = origProvider.$get;
origProvider.$get = function() {
var origInstance = instanceInjector.invoke(orig$get, origProvider);
return instanceInjector.invoke(decorFn, null, {$delegate: origInstance});
};
}
////////////////////////////////////
// internal Injector
////////////////////////////////////
function createInternalInjector(cache, factory) {
function getService(serviceName) {
if (cache.hasOwnProperty(serviceName)) {
if (cache[serviceName] === INSTANTIATING) {
throw new Error("Circular dependency found: " + path.join(' <- '));
}
return cache[serviceName];
} else {
try {
path.unshift(serviceName);
cache[serviceName] = INSTANTIATING;
return cache[serviceName] = factory(serviceName);
} catch (err) {
if (cache[serviceName] === INSTANTIATING) {
delete cache[serviceName];
}
throw err;
} finally {
path.shift();
}
}
}
function invoke(fn, self, locals){
var args = [],
$inject = annotate(fn),
length, i,
key;
for(i = 0, length = $inject.length; i < length; i++) {
key = $inject[i];
if (typeof key !== 'string') {
throw new Error("Incorrect injection token! Expected service name as string");
}
args.push(
locals && locals.hasOwnProperty(key)
? locals[key]
: getService(key)
);
}
if (!fn.$inject) {
// this means that we must be an array.
fn = fn[length];
}
// http://jsperf.com/angularjs-invoke-apply-vs-switch
// #5388
return fn.apply(self, args);
}
function instantiate(Type, locals) {
var Constructor = function() {},
instance, returnedValue;
// Check if Type is annotated and use just the given function at n-1 as parameter
// e.g. someModule.factory('greeter', ['$window', function(renamed$window) {}]);
Constructor.prototype = (isArray(Type) ? Type[Type.length - 1] : Type).prototype;
instance = new Constructor();
returnedValue = invoke(Type, instance, locals);
return isObject(returnedValue) || isFunction(returnedValue) ? returnedValue : instance;
}
return {
invoke: invoke,
instantiate: instantiate,
get: getService,
annotate: annotate,
has: function(name) {
return providerCache.hasOwnProperty(name + providerSuffix) || cache.hasOwnProperty(name);
}
};
}
}
window['createInjector'] = createInjector;
})(window);
Raw
index.html
<!DOCTYPE html>
<html>
<head>
<title>Angular's DI</title>
</head>
<body>
<script src="/javascript/di.js"></script>
<script src="/javascript/test.js"></script>
</body>
</html>
Raw
test.js
var Foo = function($shell) {
$shell.log('Hello');
};
var ShellProviderFn = function() {
this.$get = function() {
return {
magic_symbol: '@',
log: function(what) {
console.log(this.magic_symbol + what);
}
};
};
};
var inj = createInjector();
var providerInjector = inj.pInjector;
var serviceInjector = inj.sInjector;
providerInjector.invoke(function($provide) {
$provide.provider('$shell', ShellProviderFn);
});
serviceInjector.invoke(Foo);
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