feat: add JSDoc and TS defs

index.d.ts

@@ -0,0 +1 @@
+export { default } from "./src/cssHexColorToRGBA.js";

index.js

@@ -1,2 +1,2 @@
-export { default } from "./src/cssHexColorToRGB.js";
+export { default } from "./src/cssHexColorToRGBA.js";
 

src/cssHexColorToRGBA.d.ts

@@ -0,0 +1,6 @@
+/**
+ * Converts a colour from a CSS hex colour code to an RGBA array
+ * @param {string} col CSS hex colour code
+ * @returns {[number, number, number, number]}
+ */
+export default function _default(col: string): [number, number, number, number];

src/cssHexColorToRGBA.js

@@ -0,0 +1,19 @@
+// @ts-check
+
+import expandCSSHexColor from "@chriscodesthings/expand-css-hex-color";
+import { roundToPrecision } from "more-rounding";
+
+/**
+ * Converts a colour from a CSS hex colour code to an RGBA array
+ * @param {string} col CSS hex colour code
+ * @returns {[number, number, number, number]}
+ */
+export default function (col) {
+    const hex = expandCSSHexColor(col).slice(1);
+    const r = parseInt(hex.slice(0, 2), 16);
+    const g = parseInt(hex.slice(2, 4), 16);
+    const b = parseInt(hex.slice(4, 6), 16);
+    const a = roundToPrecision(parseInt(hex.slice(6, 8), 16) / 255, 2);
+
+    return [r, g, b, a];
+}