enhance: Color Utils implementation and tests

- Make sure to use if instead of switch statements to prevent fall
  through issues.
- Add tests for Color Utils
- Add invariant error handling

Author: akamfoad

.lintstagedrc

@@ -1,3 +1,3 @@
 {
-  "{src/**/*,test/**/*}": ["npx prettier --write .", "npx eslint src/ --fix"]
+  "src/**/*": ["npx prettier --write .", "npx eslint src/ --fix"]
 }

src/tests/ColorUtils.test.ts

@@ -0,0 +1,104 @@
+import { describe, expect, it } from 'vitest';
+import ColorUtils from '../utils/ColorUtils';
+
+describe('ColorUtils', () => {
+  describe('convertHexColorToBytes', () => {
+    it('should throw if hex color has wrong value', () => {
+      // @ts-expect-error testing invalid param type
+      expect(() => ColorUtils.convertHexColorToBytes()).toThrowError(
+        'Expected hexColor param to be a string instead got undefined',
+      );
+      expect(() => ColorUtils.convertHexColorToBytes('A')).toThrowError(
+        'Expected hexColor to be of length 3, 4, 6 or 8 with 0-9 A-F characters, instead got A with length 1',
+      );
+      expect(() => ColorUtils.convertHexColorToBytes('red')).toThrowError(
+        'Expected hexColor to be of length 3, 4, 6 or 8 with 0-9 A-F characters, instead got red with length 3',
+      );
+      expect(() => ColorUtils.convertHexColorToBytes('##FFF')).toThrowError(
+        'Expected hexColor to be of length 3, 4, 6 or 8 with 0-9 A-F characters, instead got #FFF with length 4',
+      );
+    });
+
+    it('should return bytes for hex color with alpha', () => {
+      expect(ColorUtils.convertHexColorToBytes('#FFFFFFFF')).toEqual([
+        255, 255, 255, 255,
+      ]);
+      expect(ColorUtils.convertHexColorToBytes('#00000000')).toEqual([
+        0, 0, 0, 0,
+      ]);
+      expect(ColorUtils.convertHexColorToBytes('#AABBCCDD')).toEqual([
+        170, 187, 204, 221,
+      ]);
+    });
+
+    it('should return bytes with default alpha for hex color without alpha', () => {
+      expect(ColorUtils.convertHexColorToBytes('#FFFFFF')).toEqual([
+        255, 255, 255, 255,
+      ]);
+      expect(ColorUtils.convertHexColorToBytes('#000000')).toEqual([
+        0, 0, 0, 255,
+      ]);
+      expect(ColorUtils.convertHexColorToBytes('#AABBCC')).toEqual([
+        170, 187, 204, 255,
+      ]);
+    });
+
+    it('should return bytes for short hex color with alpha', () => {
+      expect(ColorUtils.convertHexColorToBytes('#FFFF')).toEqual([
+        255, 255, 255, 255,
+      ]);
+      expect(ColorUtils.convertHexColorToBytes('#0000')).toEqual([0, 0, 0, 0]);
+      expect(ColorUtils.convertHexColorToBytes('#ABCD')).toEqual([
+        170, 187, 204, 221,
+      ]);
+    });
+
+    it('should return bytes with default alpha for short hex color without alpha', () => {
+      expect(ColorUtils.convertHexColorToBytes('#FFF')).toEqual([
+        255, 255, 255, 255,
+      ]);
+      expect(ColorUtils.convertHexColorToBytes('#000')).toEqual([0, 0, 0, 255]);
+      expect(ColorUtils.convertHexColorToBytes('#ABC')).toEqual([
+        170, 187, 204, 255,
+      ]);
+    });
+
+    it('should allow to use hex color without #', () => {
+      expect(ColorUtils.convertHexColorToBytes('FFF')).toEqual([
+        255, 255, 255, 255,
+      ]);
+      expect(ColorUtils.convertHexColorToBytes('000')).toEqual([0, 0, 0, 255]);
+      expect(ColorUtils.convertHexColorToBytes('ABC')).toEqual([
+        170, 187, 204, 255,
+      ]);
+
+      expect(ColorUtils.convertHexColorToBytes('FFFA')).toEqual([
+        255, 255, 255, 170,
+      ]);
+      expect(ColorUtils.convertHexColorToBytes('000A')).toEqual([0, 0, 0, 170]);
+      expect(ColorUtils.convertHexColorToBytes('ABCA')).toEqual([
+        170, 187, 204, 170,
+      ]);
+
+      expect(ColorUtils.convertHexColorToBytes('FFFFFF')).toEqual([
+        255, 255, 255, 255,
+      ]);
+      expect(ColorUtils.convertHexColorToBytes('0A0A0A')).toEqual([
+        10, 10, 10, 255,
+      ]);
+      expect(ColorUtils.convertHexColorToBytes('0A0B0C')).toEqual([
+        10, 11, 12, 255,
+      ]);
+
+      expect(ColorUtils.convertHexColorToBytes('FFFFFF0F')).toEqual([
+        255, 255, 255, 15,
+      ]);
+      expect(ColorUtils.convertHexColorToBytes('0000000A')).toEqual([
+        0, 0, 0, 10,
+      ]);
+      expect(ColorUtils.convertHexColorToBytes('42424242')).toEqual([
+        66, 66, 66, 66,
+      ]);
+    });
+  });
+});

src/utils/ColorUtils.ts

@@ -1,33 +1,39 @@
+import { invariant } from './invariant';
+
 export default class ColorUtils {
   static convertHexColorToBytes(hexColor: string): number[] {
-    const bytes: number[] = [];
+    invariant(
+      typeof hexColor === 'string',
+      `Expected hexColor param to be a string instead got ${typeof hexColor}`,
+    );
+
     let hex = hexColor.replace('#', '');
 
-    if (!/^[0-9A-F]{3,8}$/i.test(hex)) {
-      return [0, 0, 0, 0];
+    const isHexColor =
+      /^([0-9A-F]{3}|[0-9A-F]{4}|[0-9A-F]{6}|[0-9A-F]{8})$/i.test(hex);
+
+    invariant(
+      isHexColor,
+      `Expected hexColor to be of length 3, 4, 6 or 8 with 0-9 A-F characters, instead got ${hex} with length ${hex.length}`,
+    );
+
+    const bytes: number[] = [];
+
+    if (hex.length === 3) {
+      hex += 'F';
+    } else if (hex.length === 6) {
+      hex += 'FF';
     }
 
-    switch (hex.length) {
-      // @ts-ignore
-      case 3:
-        hex += 'F';
-      // Fall through
-      case 4:
-        bytes.push(...hex.split('').map(h => parseInt(h.repeat(2), 16)));
-        break;
-      // @ts-ignore
-      case 6:
-        hex += 'FF';
-      // Fall through
-      case 8:
-        bytes.push(parseInt(hex.substr(0, 2), 16));
-        bytes.push(parseInt(hex.substr(2, 2), 16));
-        bytes.push(parseInt(hex.substr(4, 2), 16));
-        bytes.push(parseInt(hex.substr(6, 2), 16));
-        break;
-      default:
-        bytes.push(0, 0, 0, 0);
+    if (hex.length === 4) {
+      bytes.push(...hex.split('').map((h) => parseInt(h.repeat(2), 16)));
+    } else if (hex.length === 8) {
+      bytes.push(parseInt(hex.substring(0, 2), 16));
+      bytes.push(parseInt(hex.substring(2, 4), 16));
+      bytes.push(parseInt(hex.substring(4, 6), 16));
+      bytes.push(parseInt(hex.substring(6, 8), 16));
     }
+
     return bytes;
   }
 }