Add Healthcheck Result type

Summary: Adds a type for the return type of runHealthchecks()

Reviewed By: passy

Differential Revision: D18474919

fbshipit-source-id: b86968088d61d9d2d31815b4c725396cc05d8ca5

doctor/src/index.ts

@@ -34,6 +34,18 @@ type Healthcheck = {
   }>;
 };
 
+type CategoryResult = [
+  string,
+  {
+    label: string;
+    results: Array<{
+      label: string;
+      isRequired: boolean;
+      result: {hasProblem: boolean};
+    }>;
+  },
+];
+
 export function getHealthchecks(): Healthchecks {
   return {
     common: {
@@ -112,14 +124,17 @@ export function getHealthchecks(): Healthchecks {
   };
 }
 
-export async function runHealthchecks() {
+export async function runHealthchecks(): Promise<Array<CategoryResult>> {
   const environmentInfo = await getEnvInfo();
-  const healthchecks = getHealthchecks();
-  const results = await Promise.all(
-    Object.entries(healthchecks).map(async ([key, category]) => [
+  const healthchecks: Healthchecks = getHealthchecks();
+  const results: Array<CategoryResult> = (await Promise.all(
+    Object.entries(healthchecks).map(async ([key, category]) => {
+      if (!category) {
+        return null;
+      }
+      const categoryResult: CategoryResult = [
         key,
-      category
-        ? {
+        {
           label: category.label,
           results: await Promise.all(
             category.healthchecks.map(async ({label, run, isRequired}) => ({
@@ -134,10 +149,11 @@ export async function runHealthchecks() {
               }),
             })),
           ),
-          }
-        : {},
-    ]),
-  );
+        },
+      ];
+      return categoryResult;
+    }),
+  )).filter(notNull);
   return results;
 }
 
@@ -146,3 +162,7 @@ async function commandSucceeds(command: string): Promise<boolean> {
     .then(() => true)
     .catch(() => false);
 }
+
+export function notNull<T>(x: T | null | undefined): x is T {
+  return x !== null && x !== undefined;
+}