feat: add promise mode

you can now do `let [res, body] = await miniget.promise(url)`

README.md

@@ -45,7 +45,11 @@ Makes a GET request. `options` can have any properties from the [`http.request()
   ```
   Given encodings will be added to the `Accept-Encoding` header, and the response will be decoded if the server responds with encoded content.
 
-If `callback` is given, will concatenate the response, and call `callback` with a possible error, the response, and the response body.
+If `callback` is given, will concatenate the response, and call `callback` with a possible error, the response, and the response body. If you'd like a concatenated response, but want to use `await` instead, you can call `miniget.promise()`.
+
+```js
+let [res, body] = await miniget.promise('http://yourwebsite.com');
+```
 
 Miniget returns a readable stream if `callback` is not given, errors will then be emitted on the stream. Returned stream also contains an `.abort()` method, and can emit the following events.
 

src/index.ts

@@ -232,4 +232,17 @@ function Miniget(url: string, options?: Miniget.Options | Callback, callback?: C
   return callback ? null : stream;
 }
 
+// istanbul ignore next
+// https://github.com/istanbuljs/nyc/issues/1209
+namespace Miniget {
+  export const promise = (url: string, options?: Options): Promise<[IncomingMessage, string]> => {
+    return new Promise((resolve, reject) => {
+      Miniget(url, options, (err, res, body) => {
+        if (err) return reject(err);
+        resolve([res, body]);
+      });
+    });
+  };
+}
+
 export = Miniget;

test/request-test.ts

@@ -79,6 +79,31 @@ describe('Make a request', () => {
     });
   });
 
+  describe('with a promise', () => {
+    it('Gives contents of page', async () => {
+      const scope = nock('http://webby.com')
+        .get('/pathos')
+        .replyWithFile(200, __filename);
+      let [res, body] = await miniget.promise('http://webby.com/pathos');
+      scope.done();
+      assert.equal(res.statusCode, 200);
+      assert.ok(body.length > 100);
+    });
+
+    describe('that errors', () => {
+      it('error is caught', async () => {
+        const scope = nock('http://something.com')
+          .get('/one/two/three')
+          .replyWithError('NONONO');
+        await assert.rejects(
+          miniget.promise('http://something.com/one/two/three', { maxRetries: 0 }),
+          null, 'NONONO'
+        );
+        scope.done();
+      });
+    });
+  });
+
   describe('that errors', () => {
     it('Emits error event', (done) => {
       const scope = nock('https://mysite.com')