59 lines
1.5 KiB
TypeScript
59 lines
1.5 KiB
TypeScript
export type Provider<T = unknown> = (manager: DependencyManager) => T;
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export type ProviderGroup = {
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[key: string]: Provider | ProviderGroup;
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};
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export class DependencyManager {
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private declarations = new Map<unknown, Provider>();
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private instances = new Map();
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private resolving = new Set();
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register(dependency: Provider): void;
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register(module: ProviderGroup): void;
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register(dependencyOrModule: Provider | ProviderGroup): void;
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register(dependencyOrModule: Provider | ProviderGroup) {
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if (this.declarations.has(dependencyOrModule)) {
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throw new Error('This dependency has already been registred');
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}
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if (typeof dependencyOrModule === 'function') {
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this.declarations.set(dependencyOrModule, dependencyOrModule);
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return;
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}
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const module = dependencyOrModule;
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for (const key in module) {
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this.register(module[key]);
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}
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}
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resolve<T>(dependency: Provider<T>): T {
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if (!this.declarations.has(dependency)) {
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throw new Error('This dependency has not been registred');
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}
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if (this.instances.has(dependency)) {
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return this.instances.get(dependency) as T;
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}
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if (this.resolving.has(dependency)) {
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throw new Error('Circular dependency detected');
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}
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this.resolving.add(dependency);
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const instance = this.instanciate(dependency);
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this.resolving.delete(dependency);
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return instance;
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}
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private instanciate<T>(dependency: Provider<T>): T {
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const declaration = this.declarations.get(dependency) as Provider<T>;
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const instance = declaration(this);
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this.instances.set(dependency, instance);
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return instance;
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}
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}
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