feat: add StreamSpeed#getStreamSpeed()

Author: fent

README.md

@@ -50,6 +50,9 @@ Removes stream from group.
 ### StreamSpeed#getSpeed()
 Get current speed.
 
+### StreamSpeed#getStreamSpeed(stream)
+Get an individual's stream's current speed.
+
 ### StreamSpeed#getStreams()
 Returns a list of all streams in the group.
 
@@ -60,7 +63,7 @@ Helper method to convert `bytes` to a human readable string.
 StreamSpeed.toHuman(1500);                                  // 1.46KB
 StreamSpeed.toHuman(1024 * 1024);                           // 1MB
 StreamSpeed.toHuman(1024 * 1024 * 20.5, { timeUnit: 's' }); // 20.5MB/s
-StreamSpeed.toHuman(1024 * 1024 * 20.5, { precision: 3 });   // 20.50MB
+StreamSpeed.toHuman(1024 * 1024 * 20.5, { precision: 3 });  // 20.50MB
 ```
 
 ### Event: 'speed'

lib/index.js

@@ -120,6 +120,20 @@ module.exports = class StreamSpeed extends EventEmitter {
   }
 
 
+  /**
+   * Get an individual stream's speed.
+   *
+   * @param {Readable} stream
+   */
+  getStreamSpeed(stream) {
+    const meta = this._streams.find(m => m.stream === stream);
+    if (!meta) {
+      throw Error('Stream not found in group');
+    }
+    return meta.speedo.getSpeed();
+  }
+
+
   /**
    * Converts bytes to human readable unit.
    * Thank you Amir from StackOverflow.

test/group-test.js

@@ -48,6 +48,9 @@ describe('Create a group and write to it', () => {
       assert.equal(spy.callCount, 2);
       assert.deepEqual(spy.getCall(0).args, [500]);
       assert.deepEqual(spy.getCall(1).args, [1000]);
+      assert.equal(group.getSpeed(), 1000);
+      assert.equal(group.getStreamSpeed(s1), 500);
+      assert.equal(group.getStreamSpeed(s2), 500);
       done();
     });
   });
@@ -66,6 +69,9 @@ describe('Create a group and write to it', () => {
     assert.equal(group.getStreams().length, 2);
     s1.interval(100, 6, 200, { end: true });
     s1.on('end', () => {
+      assert.throws(() => {
+        group.getStreamSpeed(s1);
+      }, /not found/);
       assert.equal(group.getStreams().length, 1);
       assert.equal(group.getSpeed(), 0);
       done();