Merge branch 'master' of https://github.com/neurosity/eeg-pipes

Author: alexcastillo

package-lock.json

@@ -48,7 +48,7 @@
   "dependencies": {
     "dsp.js": "^1.0.1",
     "fili": "^2.0.1",
-    "rxjs": "^6.3.1"
+    "rxjs": "^6.6.3"
   },
   "devDependencies": {
     "@types/node": "^10.12.10",

package.json

@@ -0,0 +1,21 @@
+import { pipe } from "rxjs";
+import { map } from "rxjs/operators";
+
+import { sum } from "../../utils/stats";
+import { IPSD } from "../../types/psd";
+
+/**
+ * Takes a stream of PSDs and returns a stream of arrays, containing the absolute power in each channel
+ * @method absolutePower
+ * @example eeg$.pipe(epoch({ duration: 256, interval: 100, samplingRate: 256 }), fft({ bins: 256 }), sliceFFT(10, 20), absolutePower())
+ * @returns {Observable} band powers array
+ */
+export const absolutePower = () =>
+  pipe(
+    map((inputPSD: IPSD) =>
+      inputPSD.psd.reduce(
+        (acc, channel) => [...acc, sum(channel)],
+        []
+      )
+    )
+  );

src/pipes/frequency/absolutePower.ts

@@ -5,7 +5,7 @@ import { average } from "../../utils/stats";
 import { IPSD } from "../../types/psd";
 
 /**
- * Takes a stream of PSDs and returns a sream of arrays, containing the average power in each channel
+ * Takes a stream of PSDs and returns a stream of arrays, containing the average power in each channel
  * @method averagePower
  * @example eeg$.pipe(epoch({ duration: 256, interval: 100, samplingRate: 256 }), fft({ bins: 256 }), sliceFFT(10, 20), averagePower())
  * @returns {Observable} band powers array

src/pipes/frequency/averagePower.ts

@@ -1,3 +1,4 @@
+export * from "./absolutePower";
 export * from "./alphaPower";
 export * from "./averagePower";
 export * from "./betaPower";

src/pipes/frequency/index.ts

@@ -11,16 +11,17 @@ import { FREQUENCY_BANDS as defaultBands } from "../../constants";
  * @method powerByBand
  * @example eeg$.pipe(epoch({ duration: 256, interval: 100, samplingRate: 256 }), fft({ bins: 256 }), powerByBand())
  * @param {Object} [bands] Custom bands object containing corresponding names and frequency ranges
+ * @param {Function} [powerMapper] Custom mapping function to compute band power (default = averagePower)
  * @returns {Observable<Array<number>>}
  */
-export const powerByBand = (bands = defaultBands) =>
+export const powerByBand = (bands = defaultBands, powerMapper = averagePower) =>
   pipe(
     flatMap(inputPSD => {
       const entries = Object.entries(bands);
       const bandPowers = entries.map(([_, range]) =>
         of(inputPSD).pipe(
           sliceFFT(range),
-          averagePower()
+          powerMapper()
         )
       );
       const zipPowers = (...powers) =>

src/pipes/frequency/powerByBand.ts

@@ -21,13 +21,16 @@ export const addSignalQuality = ({ dataProp = defaultDataProp } = {}) =>
         : epoch[dataProp].map((_, i) => i);
       return {
         ...epoch,
-        signalQuality: epoch[dataProp].reduce(
-          (acc, curr, index) => ({
-            ...acc,
-            [names[index]]: standardDeviation(curr)
-          }),
-          {}
-        )
+        info: {
+          ...epoch.info,
+          signalQuality: epoch[dataProp].reduce(
+            (acc, curr, index) => ({
+              ...acc,
+              [names[index]]: standardDeviation(curr)
+            }),
+            {}
+          )  
+        }
       };
     })
   );