diff --git a/types/plotly.js/index.d.ts b/types/plotly.js/index.d.ts
index 3e2cc1a351..22c7eeeccd 100644
--- a/types/plotly.js/index.d.ts
+++ b/types/plotly.js/index.d.ts
@@ -278,9 +278,10 @@ export interface Layout {
 	legend: Partial<Legend>;
 	font: Partial<Font>;
 	scene: Partial<Scene>;
-	barmode: "stack" | "group" | "overlay" | "relative";
-	bargap: number;
-	bargroupgap: number;
+	barmode: 'stack' | 'group' | 'overlay' | 'relative';
+	barnorm: '' | 'fraction' | 'percent';
+	bargap: 0 | 1;
+	bargroupgap: 0 | 1;
 	selectdirection: 'h' | 'v' | 'd' | 'any';
 	hiddenlabels: string[];
 }
diff --git a/types/plotly.js/test/core-tests.ts b/types/plotly.js/test/core-tests.ts
index c24245167e..fb44e77450 100644
--- a/types/plotly.js/test/core-tests.ts
+++ b/types/plotly.js/test/core-tests.ts
@@ -141,11 +141,11 @@ const graphDiv = '#test';
 // Plotly.relayout
 // update only values within nested objects
 (() => {
-	const update = {
+	const update: Partial<Layout> = {
 		title: 'some new title', // updates the title
 		'xaxis.range': [0, 5],   // updates the xaxis range
 		'yaxis.range[1]': 15	 // updates the end of the yaxis range
-	} as Layout;
+	};
 	Plotly.relayout(graphDiv, update);
 })();
 
@@ -163,11 +163,16 @@ const graphDiv = '#test';
 //////////////////////////////////////////////////////////////////////
 // Plotly.update
 (() => {
-	const data_update = {
-		marker: { color: 'red' }
+	const data_update: Partial<PlotData> = {
+		marker: { color: 'red' },
+		type: 'bar'
 	};
-	const layout_update = {
+	const layout_update: Partial<Layout> = {
 		title: 'some new title', // updates the title
+		barmode: 'stack',
+		barnorm: 'fraction',
+		bargap: 0,
+		bargroupgap: 0,
 	};
 	Plotly.update(graphDiv, data_update, layout_update);
 })();