@nestjs/microservices/context/rpc-proxy.js

Nest - modern, fast, powerful node.js web framework (@microservices)

import { from as fromPromise, isObservable, of } from 'rxjs';
import { catchError, mergeMap } from 'rxjs/operators';
import { ExecutionContextHost } from '@nestjs/core/internal';
export class RpcProxy {
    create(targetCallback, exceptionsHandler, reportUnhandledErrors = false) {
        return async (...args) => {
            try {
                const result = await targetCallback(...args);
                return !isObservable(result)
                    ? result
                    : result.pipe(catchError(error => this.transformToObservable(this.handleError(exceptionsHandler, args, error, reportUnhandledErrors))));
            }
            catch (error) {
                return this.handleError(exceptionsHandler, args, error, reportUnhandledErrors);
            }
        };
    }
    handleError(exceptionsHandler, args, error, reportUnhandledErrors = false) {
        const host = new ExecutionContextHost(args);
        host.setType('rpc');
        return exceptionsHandler.handle(error, host, reportUnhandledErrors);
    }
    // `catchError()` would emit the stream an async filter resolves to, iterate
    // a string or an array, and fail on other plain values. Resolve what the
    // filter returns as when the handler rejects instead.
    transformToObservable(result) {
        return isObservable(result)
            ? result
            : fromPromise(Promise.resolve(result)).pipe(mergeMap(val => (isObservable(val) ? val : of(val))));
    }
}