diff --git a/x-pack/legacy/plugins/lens/public/datatable_visualization_plugin/visualization.tsx b/x-pack/legacy/plugins/lens/public/datatable_visualization_plugin/visualization.tsx
index 79333ee7f820e..d9f49dc8b7de0 100644
--- a/x-pack/legacy/plugins/lens/public/datatable_visualization_plugin/visualization.tsx
+++ b/x-pack/legacy/plugins/lens/public/datatable_visualization_plugin/visualization.tsx
@@ -15,6 +15,7 @@ import {
   Visualization,
   VisualizationProps,
   VisualizationSuggestion,
+  Operation,
 } from '../types';
 import { generateId } from '../id_generator';
 import { NativeRenderer } from '../native_renderer';
@@ -180,7 +181,7 @@ export const datatableVisualization: Visualization<
     const datasource = frame.datasourceLayers[layer.layerId];
     const operations = layer.columns
       .map(columnId => ({ columnId, operation: datasource.getOperationForColumnId(columnId) }))
-      .filter(o => o.operation);
+      .filter((o): o is { columnId: string; operation: Operation } => !!o.operation);
 
     return {
       type: 'expression',
@@ -200,7 +201,7 @@ export const datatableVisualization: Visualization<
                       columnIds: operations.map(o => o.columnId),
                       labels: operations.map(
                         o =>
-                          o.operation!.label ||
+                          o.operation.label ||
                           i18n.translate('xpack.lens.datatable.na', {
                             defaultMessage: 'N/A',
                           })
diff --git a/x-pack/legacy/plugins/lens/public/editor_frame_plugin/embeddable/embeddable.tsx b/x-pack/legacy/plugins/lens/public/editor_frame_plugin/embeddable/embeddable.tsx
index 318cff621a9d9..728676b2ea869 100644
--- a/x-pack/legacy/plugins/lens/public/editor_frame_plugin/embeddable/embeddable.tsx
+++ b/x-pack/legacy/plugins/lens/public/editor_frame_plugin/embeddable/embeddable.tsx
@@ -63,7 +63,7 @@ export class Embeddable extends AbstractEmbeddable<LensEmbeddableInput, LensEmbe
       initialInput,
       {
         defaultTitle: savedVis.title,
-        savedObjectId: savedVis.id!,
+        savedObjectId: savedVis.id,
         editable,
         // passing edit url and index patterns to the output of this embeddable for
         // the container to pick them up and use them to configure filter bar and
diff --git a/x-pack/legacy/plugins/lens/public/editor_frame_plugin/plugin.tsx b/x-pack/legacy/plugins/lens/public/editor_frame_plugin/plugin.tsx
index 757318eff2732..11446be472cc1 100644
--- a/x-pack/legacy/plugins/lens/public/editor_frame_plugin/plugin.tsx
+++ b/x-pack/legacy/plugins/lens/public/editor_frame_plugin/plugin.tsx
@@ -14,7 +14,6 @@ import {
   EmbeddablePlugin,
   embeddablePlugin,
 } from '../../../../../../src/legacy/core_plugins/embeddable_api/public';
-import { ExpressionRenderer } from '../../../../../../src/legacy/core_plugins/data/public';
 import { setup as data } from '../../../../../../src/legacy/core_plugins/data/public/legacy';
 import { ExpressionFunction } from '../../../../../../src/legacy/core_plugins/interpreter/public';
 import { functionsRegistry } from '../../../../../../src/legacy/core_plugins/interpreter/public/registries';
@@ -40,61 +39,59 @@ export interface InterpreterSetup {
 export class EditorFramePlugin {
   constructor() {}
 
-  private ExpressionRenderer: ExpressionRenderer | null = null;
   private readonly datasources: Record<string, Datasource> = {};
   private readonly visualizations: Record<string, Visualization> = {};
 
-  private createInstance(): EditorFrameInstance {
-    let domElement: Element;
-    return {
-      mount: (element, { doc, onError, dateRange, query, onChange }) => {
-        domElement = element;
-        const firstDatasourceId = Object.keys(this.datasources)[0];
-        const firstVisualizationId = Object.keys(this.visualizations)[0];
-
-        render(
-          <I18nProvider>
-            <EditorFrame
-              data-test-subj="lnsEditorFrame"
-              onError={onError}
-              datasourceMap={this.datasources}
-              visualizationMap={this.visualizations}
-              initialDatasourceId={(doc && doc.activeDatasourceId) || firstDatasourceId || null}
-              initialVisualizationId={
-                (doc && doc.visualizationType) || firstVisualizationId || null
-              }
-              ExpressionRenderer={this.ExpressionRenderer!}
-              doc={doc}
-              dateRange={dateRange}
-              query={query}
-              onChange={onChange}
-            />
-          </I18nProvider>,
-          domElement
-        );
-      },
-      unmount() {
-        if (domElement) {
-          unmountComponentAtNode(domElement);
-        }
-      },
-    };
-  }
-
   public setup(_core: CoreSetup | null, plugins: EditorFrameSetupPlugins): EditorFrameSetup {
     plugins.interpreter.functionsRegistry.register(() => mergeTables);
 
-    this.ExpressionRenderer = plugins.data.expressions.ExpressionRenderer;
     plugins.embeddables.addEmbeddableFactory(
       new EmbeddableFactory(
         plugins.chrome,
-        this.ExpressionRenderer,
+        plugins.data.expressions.ExpressionRenderer,
         plugins.data.indexPatterns.indexPatterns
       )
     );
 
+    const createInstance = (): EditorFrameInstance => {
+      let domElement: Element;
+      return {
+        mount: (element, { doc, onError, dateRange, query, onChange }) => {
+          domElement = element;
+          const firstDatasourceId = Object.keys(this.datasources)[0];
+          const firstVisualizationId = Object.keys(this.visualizations)[0];
+
+          render(
+            <I18nProvider>
+              <EditorFrame
+                data-test-subj="lnsEditorFrame"
+                onError={onError}
+                datasourceMap={this.datasources}
+                visualizationMap={this.visualizations}
+                initialDatasourceId={(doc && doc.activeDatasourceId) || firstDatasourceId || null}
+                initialVisualizationId={
+                  (doc && doc.visualizationType) || firstVisualizationId || null
+                }
+                ExpressionRenderer={plugins.data.expressions.ExpressionRenderer}
+                doc={doc}
+                dateRange={dateRange}
+                query={query}
+                onChange={onChange}
+              />
+            </I18nProvider>,
+            domElement
+          );
+        },
+        unmount() {
+          if (domElement) {
+            unmountComponentAtNode(domElement);
+          }
+        },
+      };
+    };
+
     return {
-      createInstance: this.createInstance.bind(this),
+      createInstance,
       registerDatasource: (name, datasource) => {
         this.datasources[name] = datasource as Datasource<unknown, unknown>;
       },
diff --git a/x-pack/legacy/plugins/lens/public/indexpattern_plugin/field_item.tsx b/x-pack/legacy/plugins/lens/public/indexpattern_plugin/field_item.tsx
index e3a3802320aaa..6911212094f65 100644
--- a/x-pack/legacy/plugins/lens/public/indexpattern_plugin/field_item.tsx
+++ b/x-pack/legacy/plugins/lens/public/indexpattern_plugin/field_item.tsx
@@ -20,11 +20,11 @@ function wrapOnDot(str?: string) {
   // u200B is a non-width white-space character, which allows
   // the browser to efficiently word-wrap right after the dot
   // without us having to draw a lot of extra DOM elements, etc
-  return str ? str.replace(/\./g, '.\u200B') : undefined;
+  return str ? str.replace(/\./g, '.\u200B') : '';
 }
 
 export function FieldItem({ field, indexPatternId, highlight }: FieldItemProps) {
-  const wrappableName = wrapOnDot(field.name)!;
+  const wrappableName = wrapOnDot(field.name);
   const wrappableHighlight = wrapOnDot(highlight);
   const highlightIndex = wrappableHighlight
     ? wrappableName.toLowerCase().indexOf(wrappableHighlight.toLowerCase())
@@ -35,8 +35,8 @@ export function FieldItem({ field, indexPatternId, highlight }: FieldItemProps)
     ) : (
       <span>
         <span>{wrappableName.substr(0, highlightIndex)}</span>
-        <strong>{wrappableName.substr(highlightIndex, wrappableHighlight!.length)}</strong>
-        <span>{wrappableName.substr(highlightIndex + wrappableHighlight!.length)}</span>
+        <strong>{wrappableName.substr(highlightIndex, wrappableHighlight.length)}</strong>
+        <span>{wrappableName.substr(highlightIndex + wrappableHighlight.length)}</span>
       </span>
     );
 
diff --git a/x-pack/legacy/plugins/lens/public/indexpattern_plugin/operation_definitions/terms.tsx b/x-pack/legacy/plugins/lens/public/indexpattern_plugin/operation_definitions/terms.tsx
index 6964e9fb89f3b..2b912f827fe11 100644
--- a/x-pack/legacy/plugins/lens/public/indexpattern_plugin/operation_definitions/terms.tsx
+++ b/x-pack/legacy/plugins/lens/public/indexpattern_plugin/operation_definitions/terms.tsx
@@ -59,16 +59,19 @@ export const termsOperation: OperationDefinition<TermsIndexPatternColumn> = {
     return [];
   },
   buildColumn({ suggestedPriority, columns, field }) {
+    if (!field) {
+      throw new Error('Invariant error: terms operation requires field');
+    }
     const existingMetricColumn = Object.entries(columns)
       .filter(([_columnId, column]) => column && isSortableByColumn(column))
       .map(([id]) => id)[0];
 
     return {
-      label: ofName(field ? field.name : ''),
-      dataType: field!.type as DataType,
+      label: ofName(field.name),
+      dataType: field.type as DataType,
       operationType: 'terms',
       suggestedPriority,
-      sourceField: field ? field.name : '',
+      sourceField: field.name,
       isBucketed: true,
       params: {
         size: DEFAULT_SIZE,