feat: move toPromise to prototype

Calling from the prototype makes more sense than having to wrap a
stream.

Deprecates the `.toPromise(stream)` method.

src/PureStream.spec.ts

@@ -62,7 +62,7 @@ describe('PureStream', () => {
   });
 
   describe('wrap', () => {
-    it('wraps native stream', (done) => {
+    it('wraps node stream', (done) => {
       const source = new PassThrough({ objectMode: true });
       const dest = new PureStream();
 
@@ -77,7 +77,7 @@ describe('PureStream', () => {
       source.destroy(new Error('test'));
     });
 
-    it('wraps native stream with multiple errors', (done) => {
+    it('wraps node stream with multiple errors', (done) => {
       const source = new PassThrough({ objectMode: true });
       const dest = new PureStream();
 

src/PureStream.ts

@@ -205,6 +205,18 @@ export class PureStream<In, Out = In> {
     return stream;
   }
 
+  /** Convert this PureStream into a promise for an array of each value in the stream */
+  public toPromise() {
+    return new Promise<Out[]>((resolve, reject) => {
+      const accumulated: Out[] = [];
+
+      this.each((value) => accumulated.push(value)).done((err) => {
+        if (err) reject(err);
+        else resolve(accumulated);
+      });
+    });
+  }
+
   public static wrap<T>(source: Readable): PureStream<T>;
   public static wrap<T>(source: PassThrough): PureStream<T>;
   public static wrap<In, Out>(source: Transform): PureStream<In, Out>;

src/methods/to.ts

@@ -1,19 +1,27 @@
-import { reduce } from "./reduce";
-import { PureStream } from "../PureStream";
+import { reduce } from './reduce';
+import { PureStream } from '../PureStream';
 
 /**
  * Convert a stream into a promise for an array of values.
  * This consumes the stream.
  */
 export function toPromise<In, Out = In>(stream: PureStream<In, Out>) {
+  // eslint-disable-next-line no-console
+  console.trace(
+    'Call to deprecated method `toPromise(stream)`; please use `PureStream.prototype.toPromise()`'
+  );
+
   return new Promise<Out[]>((resolve, reject) => {
-    stream.pipe(reduce<Out, Out[]>(async (prev, next) => {
-      prev.push(next);
-      return prev;
-    }, []))
+    stream
+      .pipe(
+        reduce<Out, Out[]>(async (prev, next) => {
+          prev.push(next);
+          return prev;
+        }, [])
+      )
       .each(resolve)
       .done((err) => {
         if (err) reject(err);
-      })
+      });
   });
 }