##// END OF EJS Templates
WIP service descriptors
WIP service descriptors

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r13:dc3d64c43573 default
r13:dc3d64c43573 default
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DescriptorImpl.ts
104 lines | 2.9 KiB | video/mp2t | TypeScriptLexer
/ src / main / ts / DescriptorImpl.ts
import { Descriptor, ILifetime, DepsMap, IActivationContext, DescriptorMap } from "./interfaces";
import { each, key } from "./traits";
export interface DescriptorImplArgs<S, T> {
lifetime: ILifetime<T>;
factory: (refs: Record<key, unknown>) => NonNullable<T>;
cleanup?: (item: NonNullable<T>) => void;
overrides?: DescriptorMap<S>;
dependencies?: DepsMap<S>;
}
export const containerSelfDescriptor = <S>() => Object.freeze({
level: 0,
activate(context: IActivationContext<S>) {
return context.createChildContainer();
}
});
export class DescriptorImpl<S, T> implements Descriptor<S, T> {
private readonly _overrides?: DescriptorMap<S>;
private readonly _lifetime: ILifetime<T>;
private readonly _factory: (refs: Record<key, unknown>) => NonNullable<T>;
private readonly _cleanup?: (item: NonNullable<T>) => void;
private readonly _deps?: DepsMap<S>;
readonly hasOverrides: boolean;
constructor({ lifetime, factory, cleanup, overrides, dependencies }: DescriptorImplArgs<S, T>) {
this._lifetime = lifetime;
this._factory = factory;
if (cleanup)
this._cleanup = cleanup;
if (overrides)
this._overrides = overrides;
if (dependencies)
this._deps = dependencies;
this.hasOverrides = !!overrides;
}
activate(context: IActivationContext<S>): NonNullable<T> {
const { has, get, initialize, store } = this._lifetime(context);
if (has())
return get();
initialize();
if (this._overrides)
each(this._overrides, (v, k) => context.register(k, v));
const resolve = <K extends keyof S>({ name, lazy, ...opts }: { name: K; lazy?: boolean; default?: S[K] | null; }) => {
if (lazy) {
return "default" in opts ?
() => context.resolve(name, opts.default) :
() => context.resolve(name);
} else {
return "default" in opts ?
context.resolve(name, opts.default) :
context.resolve(name);
}
};
const deps = this._deps;
const refs = deps ?
Object.keys(deps)
.map(k => {
const ref = deps[k];
return typeof ref !== "object" ?
{ [k]: resolve({ name: ref }) } :
{ [k]: resolve(ref) };
})
.reduce((a, p) => ({ ...a, ...p }), {}) :
{};
try {
// call the factory method
const instance = (0,this._factory)(refs);
// store the instance
store(instance, this._cleanup);
return instance;
} catch(err) {
context.fail(err);
}
}
toString() {
return `[object DescriptorImpl, lifetime=${String(this._lifetime)}]`;
}
}