chore: Adding mainFn helpers

lib/health/trigger/changeOnFirstSuccess.ts

@@ -0,0 +1,28 @@
+import { TriggerInput } from "./TriggerInput";
+import { Trigger } from "./index";
+
+export function changeOnFirstSuccess(o: {
+  beforeFirstSuccess: Trigger;
+  afterFirstSuccess: Trigger;
+}) {
+  return async function* () {
+    const beforeFirstSuccess = o.beforeFirstSuccess();
+    let currentValue: TriggerInput = yield;
+    beforeFirstSuccess.next(currentValue);
+    for (
+      let res = await beforeFirstSuccess.next(currentValue);
+      currentValue?.lastResult !== "success" && !res.done;
+      res = await beforeFirstSuccess.next(currentValue)
+    ) {
+      currentValue = yield;
+    }
+    const afterFirstSuccess = o.afterFirstSuccess();
+    for (
+      let res = await afterFirstSuccess.next(currentValue);
+      !res.done;
+      res = await afterFirstSuccess.next(currentValue)
+    ) {
+      currentValue = yield;
+    }
+  };
+}