diff --git a/.eslintrc.js b/.eslintrc.js
index a09be21823..d80a2b9b4f 100644
--- a/.eslintrc.js
+++ b/.eslintrc.js
@@ -70,6 +70,7 @@ module.exports = {
     '@typescript-eslint/no-inferrable-types': 'off',
     'react/jsx-curly-brace-presence': ['error', { props: 'never', children: 'never' }],
     'react/prop-types': 0,
+    'prefer-template': 'error',
     'file-header/file-header': [
       'error',
       [
diff --git a/src/chart_types/partition_chart/layout/utils/calcs.ts b/src/chart_types/partition_chart/layout/utils/calcs.ts
index 08b22a8bb6..0ef19fe444 100644
--- a/src/chart_types/partition_chart/layout/utils/calcs.ts
+++ b/src/chart_types/partition_chart/layout/utils/calcs.ts
@@ -35,8 +35,8 @@ export function addOpacity(hexColorString: string, opacity: Ratio) {
     ? hexColorString
     : hexColorString.slice(0, 7) +
         (hexColorString.slice(7).length === 0 || parseInt(hexColorString.slice(7, 2), 16) === 255
-          ? ('00' + Math.round(opacity * 255).toString(16)).substr(-2) // color was of full opacity
-          : ('00' + Math.round((parseInt(hexColorString.slice(7, 2), 16) / 255) * opacity * 255).toString(16)).substr(
+          ? `00${Math.round(opacity * 255).toString(16)}`.substr(-2) // color was of full opacity
+          : `00${Math.round((parseInt(hexColorString.slice(7, 2), 16) / 255) * opacity * 255).toString(16)}`.substr(
               -2,
             ));
 }
diff --git a/src/chart_types/partition_chart/layout/viewmodel/fill_text_layout.ts b/src/chart_types/partition_chart/layout/viewmodel/fill_text_layout.ts
index 9c8e0bc9e3..6fc88f41e0 100644
--- a/src/chart_types/partition_chart/layout/viewmodel/fill_text_layout.ts
+++ b/src/chart_types/partition_chart/layout/viewmodel/fill_text_layout.ts
@@ -62,7 +62,7 @@ function angleToCircline(
 
 // todo pick a better unique key for the slices (D3 doesn't keep track of an index)
 export function nodeId(node: ShapeTreeNode): string {
-  return node.x0 + '|' + node.y0;
+  return `${node.x0}|${node.y0}`;
 }
 
 export function rectangleConstruction(node: ShapeTreeNode) {