Use neater spread operator to copy objects

Rather than Object.assign, I now use the ... operator to
ensure that dictionaries don't pollute each other in computed
properties.

openflexure_microscope/api/static/src/components/tabContentComponents/captureComponents/paneCapture.vue

@@ -441,18 +441,6 @@ export default {
     },
 
     scanPayload: function() {
-      var payload = Object.assign({}, this.basePayload);
-
-      // Scan params
-      payload.grid = [this.scanSteps.x, this.scanSteps.y, this.scanSteps.z];
-      payload.stride_size = [
-        this.scanStepSize.x,
-        this.scanStepSize.y,
-        this.scanStepSize.z
-      ];
-      payload.style = this.scanStyle.toLowerCase();
-      payload.namemode = this.namingStyle.toLowerCase();
-
       // Convert AF selector to dz
       var afDeltas = {
         Off: 0,
@@ -461,22 +449,32 @@ export default {
         Fine: 10,
         Fast: 2000
       };
-
+      return {
-      payload.autofocus_dz = afDeltas[this.scanDeltaZ];
+        ...this.basePayload,
-      payload.fast_autofocus = this.scanDeltaZ == "Fast";
+        // Scan params
-
+        grid: [this.scanSteps.x, this.scanSteps.y, this.scanSteps.z],
-      return payload;
+        stride_size: [
+          this.scanStepSize.x,
+          this.scanStepSize.y,
+          this.scanStepSize.z
+        ],
+        style: this.scanStyle.toLowerCase(),
+        namemode: this.namingStyle.toLowerCase(),
+        autofocus_dz: afDeltas[this.scanDeltaZ],
+        fast_autofocus: this.scanDeltaZ == "Fast"
+      };
     },
     smartScanPayload: function() {
-      var payload = Object.assign({}, this.scanPayload);
+      return {
-      payload.threshold = this.smartStackThreshold;
+        ...this.scanPayload,
-      payload.width = this.smartStackPeakWidth;
+        threshold: this.smartStackThreshold,
-      payload.align_dist = this.smartStackAlignDist;
+        width: this.smartStackPeakWidth,
-      payload.backlash = this.smartStackBacklash;
+        align_dist: this.smartStackAlignDist,
-      payload.fit_style = this.smartStackFitStyle;
+        backlash: this.smartStackBacklash,
-      payload.m_and_m_index = this.smartStackMAndMIndex;
+        fit_style: this.smartStackFitStyle,
-      payload.autofocus_dz = this.smartStackAutofocusDz;
+        m_and_m_index: this.smartStackMAndMIndex,
-      return payload;
+        autofocus_dz: this.smartStackAutofocusDz
+      };
     }
   },