@loopback/context
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Facilities to manage artifacts and their dependencies in your Node.js applications. The module exposes TypeScript/JavaScript APIs and decorators to register artifacts, declare dependencies, and resolve artifacts by keys. It also serves as an IoC container
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JavaScript
;
// Copyright IBM Corp. and LoopBack contributors 2019. All Rights Reserved.
// Node module: @loopback/context
// This file is licensed under the MIT License.
// License text available at https://opensource.org/licenses/MIT
Object.defineProperty(exports, "__esModule", { value: true });
exports.config = void 0;
const binding_key_1 = require("./binding-key");
const context_view_1 = require("./context-view");
const inject_1 = require("./inject");
const value_promise_1 = require("./value-promise");
/**
* Inject a property from `config` of the current binding. If no corresponding
* config value is present, `undefined` will be injected as the configuration
* binding is resolved with `optional: true` by default.
*
* @example
* ```ts
* class Store {
* constructor(
* @config('x') public optionX: number,
* @config('y') public optionY: string,
* ) { }
* }
*
* ctx.configure('store1', { x: 1, y: 'a' });
* ctx.configure('store2', { x: 2, y: 'b' });
*
* ctx.bind('store1').toClass(Store);
* ctx.bind('store2').toClass(Store);
*
* const store1 = ctx.getSync('store1');
* expect(store1.optionX).to.eql(1);
* expect(store1.optionY).to.eql('a');
*
* const store2 = ctx.getSync('store2');
* expect(store2.optionX).to.eql(2);
* expect(store2.optionY).to.eql('b');
* ```
*
* @param propertyPath - Optional property path of the config. If is `''` or not
* present, the `config` object will be returned.
* @param metadata - Optional metadata to help the injection
*/
function config(propertyPath, metadata) {
propertyPath = propertyPath !== null && propertyPath !== void 0 ? propertyPath : '';
if (typeof propertyPath === 'object') {
metadata = propertyPath;
propertyPath = '';
}
metadata = Object.assign({ propertyPath, decorator: '@config', optional: true }, metadata);
return (0, inject_1.inject)('', metadata, resolveFromConfig);
}
exports.config = config;
(function (config) {
/**
* `@inject.getter` decorator to inject a config getter function
* @param propertyPath - Optional property path of the config object
* @param metadata - Injection metadata
*/
config.getter = function injectConfigGetter(propertyPath, metadata) {
propertyPath = propertyPath !== null && propertyPath !== void 0 ? propertyPath : '';
if (typeof propertyPath === 'object') {
metadata = propertyPath;
propertyPath = '';
}
metadata = Object.assign({ propertyPath, decorator: '@config.getter', optional: true }, metadata);
return (0, inject_1.inject)('', metadata, resolveAsGetterFromConfig);
};
/**
* `@inject.view` decorator to inject a config context view to allow dynamic
* changes in configuration
* @param propertyPath - Optional property path of the config object
* @param metadata - Injection metadata
*/
config.view = function injectConfigView(propertyPath, metadata) {
propertyPath = propertyPath !== null && propertyPath !== void 0 ? propertyPath : '';
if (typeof propertyPath === 'object') {
metadata = propertyPath;
propertyPath = '';
}
metadata = Object.assign({ propertyPath, decorator: '@config.view', optional: true }, metadata);
return (0, inject_1.inject)('', metadata, resolveAsViewFromConfig);
};
})(config || (exports.config = config = {}));
/**
* Get the key for the current binding on which dependency injection is
* performed
* @param session - Resolution session
*/
function getCurrentBindingKey(session) {
var _a;
// The current binding is not set if `instantiateClass` is invoked directly
return (_a = session.currentBinding) === null || _a === void 0 ? void 0 : _a.key;
}
/**
* Get the target binding key from which the configuration should be resolved
* @param injection - Injection
* @param session - Resolution session
*/
function getTargetBindingKey(injection, session) {
return injection.metadata.fromBinding || getCurrentBindingKey(session);
}
/**
* Resolver for `@config`
* @param ctx - Context object
* @param injection - Injection metadata
* @param session - Resolution session
*/
function resolveFromConfig(ctx, injection, session) {
const bindingKey = getTargetBindingKey(injection, session);
// Return `undefined` if no current binding is present
if (!bindingKey)
return undefined;
const meta = injection.metadata;
return ctx.getConfigAsValueOrPromise(bindingKey, meta.propertyPath, {
session,
optional: meta.optional,
});
}
/**
* Resolver from `@config.getter`
* @param ctx - Context object
* @param injection - Injection metadata
* @param session - Resolution session
*/
function resolveAsGetterFromConfig(ctx, injection, session) {
(0, inject_1.assertTargetType)(injection, Function, 'Getter function');
const bindingKey = getTargetBindingKey(injection, session);
const meta = injection.metadata;
return async function getter() {
// Return `undefined` if no current binding is present
if (!bindingKey)
return undefined;
return ctx.getConfigAsValueOrPromise(bindingKey, meta.propertyPath, {
// https://github.com/loopbackio/loopback-next/issues/9041
// We should start with a new session for `getter` resolution to avoid
// possible circular dependencies
session: undefined,
optional: meta.optional,
});
};
}
/**
* Resolver for `@config.view`
* @param ctx - Context object
* @param injection - Injection metadata
* @param session - Resolution session
*/
function resolveAsViewFromConfig(ctx, injection, session) {
(0, inject_1.assertTargetType)(injection, context_view_1.ContextView);
const bindingKey = getTargetBindingKey(injection, session);
// Return `undefined` if no current binding is present
if (!bindingKey)
return undefined;
const view = new ConfigView(ctx, binding => binding.key === binding_key_1.BindingKey.buildKeyForConfig(bindingKey).toString(), injection.metadata.propertyPath);
view.open();
return view;
}
/**
* A subclass of `ContextView` to handle dynamic configuration as its
* `values()` honors the `propertyPath`.
*/
class ConfigView extends context_view_1.ContextView {
constructor(ctx, filter, propertyPath) {
super(ctx, filter);
this.propertyPath = propertyPath;
}
/**
* Get values for the configuration with a property path
* @param session - Resolution session
*/
async values(session) {
const configValues = await super.values(session);
const propertyPath = this.propertyPath;
if (!propertyPath)
return configValues;
return configValues.map(v => (0, value_promise_1.getDeepProperty)(v, propertyPath));
}
}
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