Use .pipe in .import if available

Required for #71

Author: Tpt

lib/JsonLdParser.ts

@@ -2,7 +2,7 @@ import * as RDF from "@rdfjs/types";
 // tslint:disable-next-line:no-var-requires
 const Parser = require('jsonparse');
 import {ERROR_CODES, ErrorCoded, IDocumentLoader, JsonLdContext, Util as ContextUtil} from "jsonld-context-parser";
-import {PassThrough, Transform} from "readable-stream";
+import {PassThrough, Transform, Readable} from "readable-stream";
 import {EntryHandlerArrayValue} from "./entryhandler/EntryHandlerArrayValue";
 import {EntryHandlerContainer} from "./entryhandler/EntryHandlerContainer";
 import {EntryHandlerInvalidFallback} from "./entryhandler/EntryHandlerInvalidFallback";
@@ -157,12 +157,18 @@ export class JsonLdParser extends Transform implements RDF.Sink<EventEmitter, RD
    * @return {RDF.Stream} A quad stream.
    */
   public import(stream: EventEmitter): RDF.Stream {
-    const output = new PassThrough({ readableObjectMode: true });
-    stream.on('error', (error) => parsed.emit('error', error));
-    stream.on('data', (data) => output.push(data));
-    stream.on('end', () => output.push(null));
-    const parsed = output.pipe(new JsonLdParser(this.options));
-    return parsed;
+    if('pipe' in stream) {
+      stream.on('error', (error) => parsed.emit('error', error));
+      const parsed = (<Readable>stream).pipe(new JsonLdParser(this.options));
+      return parsed;
+    } else {
+      const output = new PassThrough({ readableObjectMode: true });
+      stream.on('error', (error) => parsed.emit('error', error));
+      stream.on('data', (data) => output.push(data));
+      stream.on('end', () => output.push(null));
+      const parsed = output.pipe(new JsonLdParser(this.options));
+      return parsed;
+    }
   }
 
   public _transform(chunk: any, encoding: string, callback: (error?: Error | null, data?: any) => void): void {

test/JsonLdParser-test.ts

@@ -2,6 +2,7 @@ import {JsonLdParser} from "../index";
 import arrayifyStream from 'arrayify-stream';
 const streamifyString = require('streamify-string');
 import * as RDF from "@rdfjs/types";
+import { EventEmitter } from 'events';
 import {DataFactory} from "rdf-data-factory";
 import each from 'jest-each';
 import "jest-rdf";
@@ -12445,10 +12446,34 @@ describe('JsonLdParser', () => {
       ]);
     });
 
+
+    it('should parse a bad stream', async () => {
+      const stream = new EventEmitter();
+      const result = parser.import(stream);
+      stream.emit("data", `
+        {
+          "@id": "http://example.org/node",
+          "http://example.org/p": "def"
+        }`);
+      stream.emit("end");
+      return expect(await arrayifyStream(result)).toBeRdfIsomorphic([
+        DF.quad(DF.namedNode('http://example.org/node'),
+            DF.namedNode('http://example.org/p'),
+            DF.literal('def')),
+      ]);
+    });
+
     it('should forward error events', async () => {
       const stream = new PassThrough();
       stream._read = () => stream.emit('error', new Error('my error'));
       return expect(arrayifyStream(parser.import(stream))).rejects.toThrow(new Error('my error'));
     });
+
+    it('should forward error events with a bad stream', async () => {
+      const stream = new EventEmitter();
+      const result = parser.import(stream);
+      stream.emit('error', new Error('my error'));
+      return expect(arrayifyStream(result)).rejects.toThrow(new Error('my error'));
+    });
   });
 });