From 1a26fc2762dee366d2ce7ccf24e173cdc761c70c Mon Sep 17 00:00:00 2001
From: Csaba Tuncsik <csaba@n8n.io>
Date: Thu, 20 Mar 2025 10:52:51 +0100
Subject: [PATCH] fix(editor): Add smart decimals directive (#14054)

---
 .../utils/src/number/smartDecimal.test.ts     |  35 +++
 .../@n8n/utils/src/number/smartDecimal.ts     |  13 +
 .../src/directives/n8n-smart-decimal.test.ts  | 245 ++++++++++++++++++
 .../src/directives/n8n-smart-decimal.ts       |  37 +++
 4 files changed, 330 insertions(+)
 create mode 100644 packages/@n8n/utils/src/number/smartDecimal.test.ts
 create mode 100644 packages/@n8n/utils/src/number/smartDecimal.ts
 create mode 100644 packages/frontend/@n8n/design-system/src/directives/n8n-smart-decimal.test.ts
 create mode 100644 packages/frontend/@n8n/design-system/src/directives/n8n-smart-decimal.ts

diff --git a/packages/@n8n/utils/src/number/smartDecimal.test.ts b/packages/@n8n/utils/src/number/smartDecimal.test.ts
new file mode 100644
index 0000000000..5a6e1cde44
--- /dev/null
+++ b/packages/@n8n/utils/src/number/smartDecimal.test.ts
@@ -0,0 +1,35 @@
+import { smartDecimal } from './smartDecimal';
+
+describe('smartDecimal', () => {
+	it('should return the same value if it is an integer', () => {
+		expect(smartDecimal(42)).toBe(42);
+	});
+
+	it('should return the same value if it has only one decimal place', () => {
+		expect(smartDecimal(42.5)).toBe(42.5);
+	});
+
+	it('should round to two decimal places by default', () => {
+		expect(smartDecimal(42.567)).toBe(42.57);
+	});
+
+	it('should round to the specified number of decimal places', () => {
+		expect(smartDecimal(42.567, 1)).toBe(42.6);
+	});
+
+	it('should handle negative numbers correctly', () => {
+		expect(smartDecimal(-42.567, 2)).toBe(-42.57);
+	});
+
+	it('should handle zero correctly', () => {
+		expect(smartDecimal(0)).toBe(0);
+	});
+
+	it('should handle very small numbers correctly', () => {
+		expect(smartDecimal(0.000567, 5)).toBe(0.00057);
+	});
+
+	it('should round to two decimal if it is smaller than the given one', () => {
+		expect(smartDecimal(42.56, 3)).toBe(42.56);
+	});
+});
diff --git a/packages/@n8n/utils/src/number/smartDecimal.ts b/packages/@n8n/utils/src/number/smartDecimal.ts
new file mode 100644
index 0000000000..2682e570ec
--- /dev/null
+++ b/packages/@n8n/utils/src/number/smartDecimal.ts
@@ -0,0 +1,13 @@
+export const smartDecimal = (value: number, decimals = 2): number => {
+	// Check if integer
+	if (Number.isInteger(value)) {
+		return value;
+	}
+
+	// Check if it has only one decimal place
+	if (value.toString().split('.')[1].length <= decimals) {
+		return value;
+	}
+
+	return Number(value.toFixed(decimals));
+};
diff --git a/packages/frontend/@n8n/design-system/src/directives/n8n-smart-decimal.test.ts b/packages/frontend/@n8n/design-system/src/directives/n8n-smart-decimal.test.ts
new file mode 100644
index 0000000000..2071ddcf2b
--- /dev/null
+++ b/packages/frontend/@n8n/design-system/src/directives/n8n-smart-decimal.test.ts
@@ -0,0 +1,245 @@
+import { render } from '@testing-library/vue';
+
+import { n8nSmartDecimal } from './n8n-smart-decimal';
+
+describe('Directive n8n-truncate', () => {
+	it('should leave number as is without decimals', async () => {
+		const { html } = render(
+			{
+				props: {
+					text: {
+						type: String,
+					},
+				},
+				template: '<p v-n8n-smart-decimal>{{text}}</p>',
+			},
+			{
+				props: {
+					text: '42',
+				},
+				global: {
+					directives: {
+						n8nSmartDecimal,
+					},
+				},
+			},
+		);
+		expect(html()).toBe('<p>42</p>');
+	});
+
+	it('should leave number as is without decimals with binding arg', async () => {
+		const { html } = render(
+			{
+				props: {
+					text: {
+						type: String,
+					},
+				},
+				template: '<p v-n8n-smart-decimal:3>{{text}}</p>',
+			},
+			{
+				props: {
+					text: '42',
+				},
+				global: {
+					directives: {
+						n8nSmartDecimal,
+					},
+				},
+			},
+		);
+		expect(html()).toBe('<p>42</p>');
+	});
+
+	it('should leave the number with 1 decimal', async () => {
+		const { html } = render(
+			{
+				props: {
+					text: {
+						type: String,
+					},
+				},
+				template: '<p v-n8n-smart-decimal>{{text}}</p>',
+			},
+			{
+				props: {
+					text: '42.1',
+				},
+				global: {
+					directives: {
+						n8nSmartDecimal,
+					},
+				},
+			},
+		);
+		expect(html()).toBe('<p>42.1</p>');
+	});
+
+	it('should format number to 2 decimal places by default', async () => {
+		const { html } = render(
+			{
+				props: {
+					text: {
+						type: String,
+					},
+				},
+				template: '<p v-n8n-smart-decimal>{{text}}</p>',
+			},
+			{
+				props: {
+					text: '42.123456',
+				},
+				global: {
+					directives: {
+						n8nSmartDecimal,
+					},
+				},
+			},
+		);
+		expect(html()).toBe('<p>42.12</p>');
+	});
+
+	it('should format number to 1 decimal place', async () => {
+		const { html } = render(
+			{
+				props: {
+					text: {
+						type: String,
+					},
+				},
+				template: '<p v-n8n-smart-decimal:1>{{text}}</p>',
+			},
+			{
+				props: {
+					text: '42.123456',
+				},
+				global: {
+					directives: {
+						n8nSmartDecimal,
+					},
+				},
+			},
+		);
+		expect(html()).toBe('<p>42.1</p>');
+	});
+
+	it('should format number to 3 decimal places', async () => {
+		const { html } = render(
+			{
+				props: {
+					text: {
+						type: String,
+					},
+				},
+				template: '<p v-n8n-smart-decimal:3>{{text}}</p>',
+			},
+			{
+				props: {
+					text: '42.123456',
+				},
+				global: {
+					directives: {
+						n8nSmartDecimal,
+					},
+				},
+			},
+		);
+		expect(html()).toBe('<p>42.123</p>');
+	});
+
+	it('should handle negative numbers correctly', () => {
+		const { html } = render(
+			{
+				props: {
+					text: {
+						type: String,
+					},
+				},
+				template: '<p v-n8n-smart-decimal>{{text}}</p>',
+			},
+			{
+				props: {
+					text: '-42.123456',
+				},
+				global: {
+					directives: {
+						n8nSmartDecimal,
+					},
+				},
+			},
+		);
+		expect(html()).toBe('<p>-42.12</p>');
+	});
+
+	it('should handle zero correctly', () => {
+		const { html } = render(
+			{
+				props: {
+					text: {
+						type: String,
+					},
+				},
+				template: '<p v-n8n-smart-decimal>{{text}}</p>',
+			},
+			{
+				props: {
+					text: '0',
+				},
+				global: {
+					directives: {
+						n8nSmartDecimal,
+					},
+				},
+			},
+		);
+		expect(html()).toBe('<p>0</p>');
+	});
+
+	it('should handle very small numbers correctly', () => {
+		const { html } = render(
+			{
+				props: {
+					text: {
+						type: String,
+					},
+				},
+				template: '<p v-n8n-smart-decimal:5>{{text}}</p>',
+			},
+			{
+				props: {
+					text: '0.000567',
+				},
+				global: {
+					directives: {
+						n8nSmartDecimal,
+					},
+				},
+			},
+		);
+		expect(html()).toBe('<p>0.00057</p>');
+	});
+
+	it('should format number to 2 decimal places if that has fewer decimals than the desired', async () => {
+		const { html } = render(
+			{
+				props: {
+					text: {
+						type: String,
+					},
+				},
+				template: '<p v-n8n-smart-decimal:3>{{text}}</p>',
+			},
+			{
+				props: {
+					text: '42.12',
+				},
+				global: {
+					directives: {
+						n8nSmartDecimal,
+					},
+				},
+			},
+		);
+		expect(html()).toBe('<p>42.12</p>');
+	});
+});
diff --git a/packages/frontend/@n8n/design-system/src/directives/n8n-smart-decimal.ts b/packages/frontend/@n8n/design-system/src/directives/n8n-smart-decimal.ts
new file mode 100644
index 0000000000..13f4e72b89
--- /dev/null
+++ b/packages/frontend/@n8n/design-system/src/directives/n8n-smart-decimal.ts
@@ -0,0 +1,37 @@
+import { smartDecimal } from '@n8n/utils/number/smartDecimal';
+import type { DirectiveBinding, FunctionDirective } from 'vue';
+
+/**
+ * Custom directive `n8nSmartDecimal` to format numbers with smart decimal places.
+ *
+ * Usage:
+ * In your Vue template, use the directive `v-n8n-smart-decimal` passing the number and optionally the decimal places.
+ *
+ * Example:
+ * <p v-n8n-smart-decimal>42.567</p>
+ *
+ * Compiles to: <p>42.57</p>
+ *
+ * Example with specified decimal places:
+ * <p v-n8n-smart-decimal:4>42.56789</p>
+ *
+ * Compiles to: <p>42.5679</p>
+ *
+ * Function Shorthand:
+ * https://vuejs.org/guide/reusability/custom-directives#function-shorthand
+ *
+ * Hint: Do not use it on components
+ * https://vuejs.org/guide/reusability/custom-directives#usage-on-components
+ */
+
+export const n8nSmartDecimal: FunctionDirective = (
+	el: HTMLElement,
+	binding: DirectiveBinding<number | undefined>,
+) => {
+	const value = parseFloat(el.textContent ?? '');
+	if (!isNaN(value)) {
+		const decimals = isNaN(Number(binding.arg)) ? undefined : Number(binding.arg);
+		const formattedValue = smartDecimal(value, decimals);
+		el.textContent = formattedValue.toString();
+	}
+};