Update toggle

styles/src/element/toggle.ts

@@ -0,0 +1,47 @@
+import merge from "ts-deepmerge"
+
+type ToggleState = "inactive" | "active"
+
+type Toggleable<T> = Record<ToggleState, T>
+
+const NO_INACTIVE_OR_BASE_ERROR =
+    "A toggleable object must have an inactive state, or a base property."
+const NO_ACTIVE_ERROR = "A toggleable object must have an active state."
+
+interface ToggleableProps<T> {
+    base?: T
+    state: Partial<Record<ToggleState, T>>
+}
+
+/**
+ * Helper function for creating Toggleable objects.
+ * @template T The type of the object being toggled.
+ * @param props Object containing the base (inactive) state and state modifications to create the active state.
+ * @returns A Toggleable object containing both the inactive and active states.
+ * @example
+ * ```
+ * toggleable({
+ *   base: { background: "#000000", text: "#CCCCCC" },
+ *   state: { active: { text: "#CCCCCC" } },
+ * })
+ * ```
+ */
+export function toggleable<T extends object>(
+    props: ToggleableProps<T>
+): Toggleable<T> {
+    const { base, state } = props
+
+    if (!base && !state.inactive) throw new Error(NO_INACTIVE_OR_BASE_ERROR)
+    if (!state.active) throw new Error(NO_ACTIVE_ERROR)
+
+    const inactiveState = base
+        ? ((state.inactive ? merge(base, state.inactive) : base) as T)
+        : (state.inactive as T)
+
+    const toggleObj: Toggleable<T> = {
+        inactive: inactiveState,
+        active: merge(base ?? {}, state.active) as T,
+    }
+
+    return toggleObj
+}