First commit.

Signed-off-by: Chen Xiao <abigwc@gmail.com>

client/node_modules/langium/lib/dependency-injection.js

@@ -0,0 +1,164 @@
+/******************************************************************************
+ * Copyright 2021 TypeFox GmbH
+ * This program and the accompanying materials are made available under the
+ * terms of the MIT License, which is available in the project root.
+ ******************************************************************************/
+export var Module;
+(function (Module) {
+    /**
+     * Merges two dependency injection modules into a new (third) one that is returned.
+     * At that `m1` and `m2` stay unchanged. Therefore, `m1` is deep-copied first,
+     * and m2 is merged onto the copy afterwards.
+     *
+     * Note that the leaf values of `m1` and `m2`, i.e. the service constructor functions,
+     * cannot be copied generically, since they are functions. They are shared by the source and merged modules.
+     *
+     * @returns the merged module being a deep copy of `m1` with `m2` merged onto it.
+     */
+    Module.merge = (m1, m2) => _merge(_merge({}, m1), m2);
+})(Module || (Module = {}));
+/**
+ * Given a set of modules, the inject function returns a lazily evaluated injector
+ * that injects dependencies into the requested service when it is requested the
+ * first time. Subsequent requests will return the same service.
+ *
+ * In the case of cyclic dependencies, an Error will be thrown. This can be fixed
+ * by injecting a provider `() => T` instead of a `T`.
+ *
+ * Please note that the arguments may be objects or arrays. However, the result will
+ * be an object. Using it with for..of will have no effect.
+ *
+ * @param module1 first Module
+ * @param module2 (optional) second Module
+ * @param module3 (optional) third Module
+ * @param module4 (optional) fourth Module
+ * @param module5 (optional) fifth Module
+ * @param module6 (optional) sixth Module
+ * @param module7 (optional) seventh Module
+ * @param module8 (optional) eighth Module
+ * @param module9 (optional) ninth Module
+ * @returns a new object of type I
+ */
+export function inject(module1, module2, module3, module4, module5, module6, module7, module8, module9) {
+    const module = [module1, module2, module3, module4, module5, module6, module7, module8, module9].reduce(_merge, {});
+    return _inject(module);
+}
+const isProxy = Symbol('isProxy');
+/**
+ * Eagerly load all services in the given dependency injection container. This is sometimes
+ * necessary because services can register event listeners in their constructors.
+ */
+export function eagerLoad(item) {
+    if (item && item[isProxy]) {
+        for (const value of Object.values(item)) {
+            eagerLoad(value);
+        }
+    }
+    return item;
+}
+/**
+ * Helper function that returns an injector by creating a proxy.
+ * Invariant: injector is of type I. If injector is undefined, then T = I.
+ */
+function _inject(module, injector) {
+    const proxy = new Proxy({}, {
+        deleteProperty: () => false,
+        set: () => {
+            throw new Error('Cannot set property on injected service container');
+        },
+        get: (obj, prop) => {
+            if (prop === isProxy) {
+                return true;
+            }
+            else {
+                return _resolve(obj, prop, module, injector || proxy);
+            }
+        },
+        getOwnPropertyDescriptor: (obj, prop) => (_resolve(obj, prop, module, injector || proxy), Object.getOwnPropertyDescriptor(obj, prop)), // used by for..in
+        has: (_, prop) => prop in module, // used by ..in..
+        ownKeys: () => [...Object.getOwnPropertyNames(module)] // used by for..in
+    });
+    return proxy;
+}
+/**
+ * Internally used to tag a requested dependency, directly before calling the factory.
+ * This allows us to find cycles during instance creation.
+ */
+const __requested__ = Symbol();
+/**
+ * Returns the value `obj[prop]`. If the value does not exist, yet, it is resolved from
+ * the module description. The result of service factories is cached. Groups are
+ * recursively proxied.
+ *
+ * @param obj an object holding all group proxies and services
+ * @param prop the key of a value within obj
+ * @param module an object containing groups and service factories
+ * @param injector the first level proxy that provides access to all values
+ * @returns the requested value `obj[prop]`
+ * @throws Error if a dependency cycle is detected
+ */
+function _resolve(obj, prop, module, injector) {
+    if (prop in obj) {
+        if (obj[prop] instanceof Error) {
+            throw new Error('Construction failure. Please make sure that your dependencies are constructable. Cause: ' + obj[prop]);
+        }
+        if (obj[prop] === __requested__) {
+            throw new Error('Cycle detected. Please make "' + String(prop) + '" lazy. Visit https://langium.org/docs/reference/configuration-services/#resolving-cyclic-dependencies');
+        }
+        return obj[prop];
+    }
+    else if (prop in module) {
+        const value = module[prop];
+        obj[prop] = __requested__;
+        try {
+            obj[prop] = (typeof value === 'function') ? value(injector) : _inject(value, injector);
+        }
+        catch (error) {
+            obj[prop] = error instanceof Error ? error : undefined;
+            throw error;
+        }
+        return obj[prop];
+    }
+    else {
+        return undefined;
+    }
+}
+/**
+ * Performs a deep-merge of two modules by writing source entries into the target module.
+ *
+ * @param target the module which is written
+ * @param source the module which is read
+ * @returns the target module
+ */
+function _merge(target, source) {
+    if (source) {
+        for (const [key, sourceValue] of Object.entries(source)) {
+            if (sourceValue !== undefined && sourceValue !== null) {
+                if (typeof sourceValue === 'object') {
+                    const targetValue = target[key];
+                    if (typeof targetValue === 'object' && targetValue !== null) {
+                        // in case both values are real (non-null) objects merge them recursively
+                        target[key] = _merge(targetValue, sourceValue);
+                    }
+                    else {
+                        // in case 'target[key]' is not a non-null object
+                        //  we overwrite any existing value with a deep copy of 'sourceValue'
+                        //  by recursively calling this function with a new 'target' object to be populated
+                        //  that is assigned to 'target[key]' afterwards
+                        target[key] = _merge({}, sourceValue);
+                    }
+                }
+                else {
+                    // in case 'sourceValue' is defined and assigned (non-null) but not an object
+                    //  we assume it to be a service constructor function according to the Module<I> type definition
+                    target[key] = sourceValue;
+                    // note the following for such service constructor functions:
+                    // 'target[key]' will now reference the same function object being referenced by 'source[key]'.
+                    // This is accepted here, since function objects cannot be safely copied in general.
+                }
+            }
+        }
+    }
+    return target;
+}
+//# sourceMappingURL=dependency-injection.js.map