refactor: Simplify TypedRepresentationConverter contruction.

.componentsignore

@@ -1,4 +1,5 @@
 [
   "Error",
-  "EventEmitter"
+  "EventEmitter",
+  "ValuePreferencesArg"
 ]

src/storage/conversion/ChainedConverter.ts

@@ -1,5 +1,4 @@
 import type { Representation } from '../../ldp/representation/Representation';
-import type { ValuePreferences } from '../../ldp/representation/RepresentationPreferences';
 import { getLoggerFor } from '../../logging/LogUtil';
 import { matchesMediaType } from './ConversionUtil';
 import type { RepresentationConverterArgs } from './RepresentationConverter';
@@ -25,6 +24,8 @@ export class ChainedConverter extends TypedRepresentationConverter {
       throw new Error('At least 2 converters are required.');
     }
     this.converters = [ ...converters ];
+    this.inputTypes = this.first.getInputTypes();
+    this.outputTypes = this.last.getOutputTypes();
   }
 
   protected get first(): TypedRepresentationConverter {
@@ -35,14 +36,6 @@ export class ChainedConverter extends TypedRepresentationConverter {
     return this.converters[this.converters.length - 1];
   }
 
-  public async getInputTypes(): Promise<ValuePreferences> {
-    return this.first.getInputTypes();
-  }
-
-  public async getOutputTypes(): Promise<ValuePreferences> {
-    return this.last.getOutputTypes();
-  }
-
   public async handle(input: RepresentationConverterArgs): Promise<Representation> {
     const args = { ...input };
     for (let i = 0; i < this.converters.length - 1; ++i) {

src/storage/conversion/QuadToRdfConverter.ts

@@ -3,10 +3,7 @@ import { StreamWriter } from 'n3';
 import rdfSerializer from 'rdf-serialize';
 import type { Representation } from '../../ldp/representation/Representation';
 import { RepresentationMetadata } from '../../ldp/representation/RepresentationMetadata';
-import type {
+import type { ValuePreferences } from '../../ldp/representation/RepresentationPreferences';
-  ValuePreferences,
-  RepresentationPreferences,
-} from '../../ldp/representation/RepresentationPreferences';
 import { INTERNAL_QUADS } from '../../util/ContentTypes';
 import { guardStream } from '../../util/GuardedStream';
 import { pipeSafely } from '../../util/StreamUtil';
@@ -22,26 +19,14 @@ export class QuadToRdfConverter extends TypedRepresentationConverter {
   private readonly outputPreferences?: ValuePreferences;
 
   public constructor(options: { outputPreferences?: Record<string, number> } = {}) {
-    super();
+    super(
-    if (Object.keys(options.outputPreferences ?? {}).length > 0) {
+      INTERNAL_QUADS,
-      this.outputPreferences = { ...options.outputPreferences };
+      options.outputPreferences ?? rdfSerializer.getContentTypesPrioritized(),
-    }
+    );
   }
 
-  public async getInputTypes(): Promise<ValuePreferences> {
+  public async handle({ representation: quads, preferences }: RepresentationConverterArgs): Promise<Representation> {
-    return { [INTERNAL_QUADS]: 1 };
+    const contentType = matchingMediaTypes(preferences.type, await this.getOutputTypes())[0];
-  }
-
-  public async getOutputTypes(): Promise<ValuePreferences> {
-    return this.outputPreferences ?? rdfSerializer.getContentTypesPrioritized();
-  }
-
-  public async handle(input: RepresentationConverterArgs): Promise<Representation> {
-    return this.quadsToRdf(input.representation, input.preferences);
-  }
-
-  private async quadsToRdf(quads: Representation, { type }: RepresentationPreferences): Promise<Representation> {
-    const contentType = matchingMediaTypes(type, await this.getOutputTypes())[0];
     const metadata = new RepresentationMetadata(quads.metadata, { [CONTENT_TYPE]: contentType });
     let data: Readable;
 

src/storage/conversion/RdfToQuadConverter.ts

@@ -2,7 +2,6 @@ import { PassThrough } from 'stream';
 import rdfParser from 'rdf-parse';
 import type { Representation } from '../../ldp/representation/Representation';
 import { RepresentationMetadata } from '../../ldp/representation/RepresentationMetadata';
-import type { ValuePreferences } from '../../ldp/representation/RepresentationPreferences';
 import { INTERNAL_QUADS } from '../../util/ContentTypes';
 import { BadRequestHttpError } from '../../util/errors/BadRequestHttpError';
 import { pipeSafely } from '../../util/StreamUtil';
@@ -14,23 +13,15 @@ import { TypedRepresentationConverter } from './TypedRepresentationConverter';
  * Converts most major RDF serializations to `internal/quads`.
  */
 export class RdfToQuadConverter extends TypedRepresentationConverter {
-  public async getInputTypes(): Promise<ValuePreferences> {
+  public constructor() {
-    return rdfParser.getContentTypesPrioritized();
+    super(rdfParser.getContentTypesPrioritized(), INTERNAL_QUADS);
   }
 
-  public async getOutputTypes(): Promise<ValuePreferences> {
+  public async handle({ representation, identifier }: RepresentationConverterArgs): Promise<Representation> {
-    return { [INTERNAL_QUADS]: 1 };
-  }
-
-  public async handle(input: RepresentationConverterArgs): Promise<Representation> {
-    return this.rdfToQuads(input.representation, input.identifier.path);
-  }
-
-  private rdfToQuads(representation: Representation, baseIRI: string): Representation {
     const metadata = new RepresentationMetadata(representation.metadata, { [CONTENT_TYPE]: INTERNAL_QUADS });
     const rawQuads = rdfParser.parse(representation.data, {
       contentType: representation.metadata.contentType!,
-      baseIRI,
+      baseIRI: identifier.path,
     });
 
     const pass = new PassThrough({ objectMode: true });

src/storage/conversion/TypedRepresentationConverter.ts

@@ -3,19 +3,49 @@ import { supportsMediaTypeConversion } from './ConversionUtil';
 import { RepresentationConverter } from './RepresentationConverter';
 import type { RepresentationConverterArgs } from './RepresentationConverter';
 
+type PromiseOrValue<T> = T | Promise<T>;
+type ValuePreferencesArg =
+  PromiseOrValue<string> |
+  PromiseOrValue<string[]> |
+  PromiseOrValue<ValuePreferences>;
+
+async function toValuePreferences(arg: ValuePreferencesArg): Promise<ValuePreferences> {
+  const resolved = await arg;
+  if (typeof resolved === 'string') {
+    return { [resolved]: 1 };
+  }
+  if (Array.isArray(resolved)) {
+    return Object.fromEntries(resolved.map((type): [string, number] => [ type, 1 ]));
+  }
+  return resolved;
+}
+
 /**
  * A {@link RepresentationConverter} that allows requesting the supported types.
  */
 export abstract class TypedRepresentationConverter extends RepresentationConverter {
+  protected inputTypes: Promise<ValuePreferences>;
+  protected outputTypes: Promise<ValuePreferences>;
+
+  public constructor(inputTypes: ValuePreferencesArg = {}, outputTypes: ValuePreferencesArg = {}) {
+    super();
+    this.inputTypes = toValuePreferences(inputTypes);
+    this.outputTypes = toValuePreferences(outputTypes);
+  }
+
   /**
    * Gets the supported input content types for this converter, mapped to a numerical priority.
    */
-  public abstract getInputTypes(): Promise<ValuePreferences>;
+  public async getInputTypes(): Promise<ValuePreferences> {
+    return this.inputTypes;
+  }
 
   /**
    * Gets the supported output content types for this converter, mapped to a numerical quality.
    */
-  public abstract getOutputTypes(): Promise<ValuePreferences>;
+  public async getOutputTypes(): Promise<ValuePreferences> {
+    return this.outputTypes;
+  }
 
   /**
    * Verifies whether this converter supports the input.

test/unit/storage/conversion/QuadToRdfConverter.test.ts

@@ -24,18 +24,12 @@ describe('A QuadToRdfConverter', (): void => {
       .resolves.toEqual({ [INTERNAL_QUADS]: 1 });
   });
 
-  it('defaults to rdfSerializer preferences when given no preferences.', async(): Promise<void> => {
+  it('defaults to rdfSerializer preferences when given no output preferences.', async(): Promise<void> => {
     await expect(new QuadToRdfConverter().getOutputTypes())
       .resolves.toEqual(await rdfSerializer.getContentTypesPrioritized());
   });
 
-  it('defaults to rdfSerializer preferences when given empty preferences.', async(): Promise<void> => {
+  it('supports overriding output preferences.', async(): Promise<void> => {
-    const outputPreferences = {};
-    await expect(new QuadToRdfConverter({ outputPreferences }).getOutputTypes())
-      .resolves.toEqual(await rdfSerializer.getContentTypesPrioritized());
-  });
-
-  it('returns custom preferences when given non-empty preferences.', async(): Promise<void> => {
     const outputPreferences = { 'text/turtle': 1 };
     await expect(new QuadToRdfConverter({ outputPreferences }).getOutputTypes())
       .resolves.toEqual(outputPreferences);

test/unit/storage/conversion/TypedRepresentationConverter.test.ts

@@ -0,0 +1,47 @@
+import { TypedRepresentationConverter } from '../../../../src/storage/conversion/TypedRepresentationConverter';
+
+class CustomTypedRepresentationConverter extends TypedRepresentationConverter {
+  public handle = jest.fn();
+}
+
+describe('A TypedRepresentationConverter', (): void => {
+  it('defaults to allowing everything.', async(): Promise<void> => {
+    const converter = new CustomTypedRepresentationConverter();
+    await expect(converter.getInputTypes()).resolves.toEqual({
+    });
+    await expect(converter.getOutputTypes()).resolves.toEqual({
+    });
+  });
+
+  it('accepts strings.', async(): Promise<void> => {
+    const converter = new CustomTypedRepresentationConverter('a/b', 'c/d');
+    await expect(converter.getInputTypes()).resolves.toEqual({
+      'a/b': 1,
+    });
+    await expect(converter.getOutputTypes()).resolves.toEqual({
+      'c/d': 1,
+    });
+  });
+
+  it('accepts string arrays.', async(): Promise<void> => {
+    const converter = new CustomTypedRepresentationConverter([ 'a/b', 'c/d' ], [ 'e/f', 'g/h' ]);
+    await expect(converter.getInputTypes()).resolves.toEqual({
+      'a/b': 1,
+      'c/d': 1,
+    });
+    await expect(converter.getOutputTypes()).resolves.toEqual({
+      'e/f': 1,
+      'g/h': 1,
+    });
+  });
+
+  it('accepts records.', async(): Promise<void> => {
+    const converter = new CustomTypedRepresentationConverter({ 'a/b': 0.5 }, { 'c/d': 0.5 });
+    await expect(converter.getInputTypes()).resolves.toEqual({
+      'a/b': 0.5,
+    });
+    await expect(converter.getOutputTypes()).resolves.toEqual({
+      'c/d': 0.5,
+    });
+  });
+});