diff --git a/src/components/withColumnChart.js b/src/components/withColumnChart.js
index bd52aae..ab45918 100644
--- a/src/components/withColumnChart.js
+++ b/src/components/withColumnChart.js
@@ -98,7 +98,7 @@ const withColumnChart = (ComposedComponent) => {
               this.series.forEach(s => {
                 s.data.filter((d,idx,arr) => {
                   return idx === arr.length - 1;
-                }).map(d => {
+                }).forEach(d => {
                   d.setState('hover');
                 });
               });
@@ -132,7 +132,7 @@ const withColumnChart = (ComposedComponent) => {
                   this.series.chart.series.forEach(s => {
                     s.data.filter((d,idx) => {
                       return this.index === idx;
-                    }).map(d => {
+                    }).forEach(d => {
                       d.setState && d.setState('hover');
                     });
                   });
@@ -141,7 +141,7 @@ const withColumnChart = (ComposedComponent) => {
                 mouseOut: function() {
                   // todo - extract to setHighchartsSeriesDataState
                   this.series.chart.series.forEach(s => {
-                    s.data.map(d => {
+                    s.data.forEach(d => {
                       d.setState && d.setState('');
                     });
                   });
diff --git a/src/components/withHeroChart.js b/src/components/withHeroChart.js
index 704a1cf..da63893 100644
--- a/src/components/withHeroChart.js
+++ b/src/components/withHeroChart.js
@@ -65,6 +65,9 @@ const withHeroChart = (ComposedComponent) => {
                 case 'visible':
                   this.tooltip.label.hide();
                   break;
+
+                default:
+                  // Just to shut the linter up
                 }
               }
             }
diff --git a/src/components/withLineChart.js b/src/components/withLineChart.js
index 1a46af6..7f3ab6a 100644
--- a/src/components/withLineChart.js
+++ b/src/components/withLineChart.js
@@ -79,7 +79,7 @@ const withLineChart = (ComposedComponent) => {
               this.series.forEach(s => {
                 s.data.filter((d,idx,arr) => {
                   return idx === arr.length - 1;
-                }).map(d => {
+                }).forEach(d => {
                   d.setState('hover');
                 });
               });
@@ -120,7 +120,7 @@ const withLineChart = (ComposedComponent) => {
                   this.series.chart.series.forEach(s => {
                     s.data.filter((d,idx) => {
                       return this.index === idx;
-                    }).map(d => {
+                    }).forEach(d => {
                       d.setState && d.setState('hover');
                     });
                   });
@@ -129,7 +129,7 @@ const withLineChart = (ComposedComponent) => {
                 mouseOut: function() {
                   // todo - extract to setHighchartsSeriesDataState
                   this.series.chart.series.forEach(s => {
-                    s.data.map(d => {
+                    s.data.forEach(d => {
                       d.setState && d.setState('');
                     });
                   });
diff --git a/src/components/withStackedColumnChart.js b/src/components/withStackedColumnChart.js
index 2000780..456242e 100644
--- a/src/components/withStackedColumnChart.js
+++ b/src/components/withStackedColumnChart.js
@@ -79,7 +79,7 @@ const withStackedColumnChart = (ComposedComponent) => {
               this.series.forEach(s => {
                 s.data.filter((d,idx,arr) => {
                   return idx === arr.length - 1;
-                }).map(d => {
+                }).forEach(d => {
                   d.setState('hover');
                 });
               });
@@ -115,7 +115,7 @@ const withStackedColumnChart = (ComposedComponent) => {
                   this.series.chart.series.forEach(s => {
                     s.data.filter((d,idx) => {
                       return this.index === idx;
-                    }).map(d => {
+                    }).forEach(d => {
                       d.setState('hover');
                     });
                   });
@@ -126,7 +126,7 @@ const withStackedColumnChart = (ComposedComponent) => {
                   this.series.chart.series.forEach(s => {
                     s.data.filter((d,idx) => {
                       return this.index === idx;
-                    }).map(d => {
+                    }).forEach(d => {
                       d.setState('');
                     });
                   });
diff --git a/src/utils/chartOptionsHelpers.js b/src/utils/chartOptionsHelpers.js
index 6e708a6..5417b40 100644
--- a/src/utils/chartOptionsHelpers.js
+++ b/src/utils/chartOptionsHelpers.js
@@ -65,9 +65,7 @@ export const plotNullDataLayerToAxis = (xAxis, series, broadcastSetState) => {
 
   const idxsWithNullValue = series.map(s => {
     return s.data.map((d, idx) => {
-      if (d.y === null) {
-        return idx;
-      }
+      return d.y === null ? idx : undefined; // For the linter's sake
     });
   }).reduce((a,b) => {
     // find an intersection between the arrays - common null vals in a series set
@@ -91,7 +89,7 @@ export const plotNullDataLayerToAxis = (xAxis, series, broadcastSetState) => {
               broadcastSetState({'customLegend': createCartesianCustomLegendData(this.axis.series, idx)});
             this.axis.crosshair = false;
             this.axis.series.forEach(s => {
-              s.data.map(d => {
+              s.data.forEach(d => {
                 d.setState('');
               });
             });