add computedResult

houston-common-ui/lib/composables/computedResult.ts

@@ -0,0 +1,33 @@
+import { ResultAsync, Result } from "neverthrow";
+import { watchEffect, ref, type Ref } from "vue";
+
+/**
+ * Create a computed ref that grabs it's value from a {@link Result} or {@link ResultAsync},
+ * returning computed ref and a manual update trigger function.
+ * @param getter function that returns a result of T
+ * @returns [reference: ComputedRef\<T | undefined\>, triggerUpdate: () => void]
+ */
+export function computedResult<T>(
+  getter: () => Result<T, any> | ResultAsync<T, any>
+): [reference: Readonly<Ref<T | undefined>>, triggerUpdate: () => void];
+/**
+ * Create a computed ref with default value that grabs it's value from a {@link Result} or {@link ResultAsync},
+ * returning computed ref and a manual update trigger function.
+ * @param getter function that returns a result of T
+ * @param defaultValue the default value before the Result is determined
+ * @returns [reference: ComputedRef\<T\>, triggerUpdate: () => void]
+ */
+export function computedResult<T>(
+  getter: () => Result<T, any> | ResultAsync<T, any>,
+  defaultValue: T
+): [reference: Readonly<Ref<T>>, triggerUpdate: () => void];
+export function computedResult<T>(
+  getter: () => Result<T, any> | ResultAsync<T, any>,
+  defaultValue?: T
+): [reference: Readonly<Ref<T | undefined>>, triggerUpdate: () => void] {
+  const reference = ref<T>();
+  reference.value = defaultValue;
+  const triggerUpdate = () => getter().map((v) => (reference.value = v));
+  watchEffect(triggerUpdate);
+  return [reference, triggerUpdate];
+}

houston-common-ui/lib/composables/index.ts

@@ -7,3 +7,4 @@ export {
   confirmBeforeAction,
   assertConfirm,
 } from "./globalModalConfirm";
+export * from "./computedResult";