refactor

Signed-off-by: Francis <colifran@amazon.com>

packages/@aws-cdk/custom-resource-handlers/lib/custom-resources/aws-custom-resource-handler/index.ts

@@ -9,7 +9,7 @@ import { ApiCall } from '@aws-cdk/aws-custom-resource-sdk-adapter';
 import type * as AWSLambda from 'aws-lambda';
 import type { AwsSdkCall } from './construct-types';
 import { loadAwsSdk } from './load-sdk';
-import { decodeCall, decodeSpecialValues, filterKeys, startsWithOneOf, respond, getCredentials } from './utils';
+import { decodeCall, decodeSpecialValues, respond, getCredentials, formatData } from './utils';
 
 /* eslint-disable @typescript-eslint/no-require-imports, import/no-extraneous-dependencies */
 export async function handler(event: AWSLambda.CloudFormationCustomResourceEvent, context: AWSLambda.Context): Promise<void> {
@@ -65,18 +65,7 @@ export async function handler(event: AWSLambda.CloudFormationCustomResourceEvent
         flatData.region = await apiCall.client.config.region().catch(() => undefined); // For test purposes: check if region was correctly passed.
         Object.assign(flatData, response);
 
-        let outputPaths: string[] | undefined;
-        if (call.outputPath) {
-          outputPaths = [call.outputPath];
-        } else if (call.outputPaths) {
-          outputPaths = call.outputPaths;
-        }
-
-        if (outputPaths) {
-          data = filterKeys(flatData, startsWithOneOf(outputPaths));
-        } else {
-          data = flatData;
-        }
+        data = formatData(call, flatData);
       } catch (e: any) {
         // empirecal evidence show e.name is not always set
         const exceptionName = e.name ?? e.constructor.name;

packages/@aws-cdk/custom-resource-handlers/lib/custom-resources/aws-custom-resource-handler/utils.ts

@@ -33,19 +33,6 @@ export function decodeSpecialValues(object: object, physicalResourceId: string):
   }
 }
 
-/**
- * Filters the keys of an object.
- */
-export function filterKeys(object: object, pred: (key: string) => boolean): {} {
-  return Object.entries(object)
-    .reduce(
-      (acc, [k, v]) => pred(k)
-        ? { ...acc, [k]: v }
-        : acc,
-      {},
-    );
-}
-
 /**
  * Parses a stringified JSON API call.
  */
@@ -54,17 +41,6 @@ export function decodeCall(call: string | undefined): any {
   return JSON.parse(call);
 }
 
-export function startsWithOneOf(searchStrings: string[]): (string: string) => boolean {
-  return function(string: string): boolean {
-    for (const searchString of searchStrings) {
-      if (string.startsWith(searchString)) {
-        return true;
-      }
-    }
-    return false;
-  };
-}
-
 /**
  * Responds to the CloudFormation Custom Resource.
  */
@@ -140,3 +116,49 @@ export async function getCredentials(call: AwsSdkCall, physicalResourceId: strin
   }
   return credentials;
 }
+
+/**
+ * Formats API response data based on outputPath or outputPaths configured in the SDK call.
+ */
+export function formatData(call: AwsSdkCall, flatData: { [key: string]: string }): { [key: string]: string } {
+  let outputPaths: string[] | undefined;
+  if (call.outputPath) {
+    outputPaths = [call.outputPath];
+  } else if (call.outputPaths) {
+    outputPaths = call.outputPaths;
+  }
+
+  if (outputPaths) {
+    return filterKeys(flatData, startsWithOneOf(outputPaths));
+  }
+
+  return flatData;
+}
+
+/**
+ * Returns a predicate function that returns true if a target string starts with any of the specified
+ * search strings.
+ */
+function startsWithOneOf(searchStrings: string[]): (string: string) => boolean {
+  return function(string: string): boolean {
+    for (const searchString of searchStrings) {
+      if (string.startsWith(searchString)) {
+        return true;
+      }
+    }
+    return false;
+  };
+}
+
+/**
+ * Filters the keys of an object.
+ */
+function filterKeys(object: object, pred: (key: string) => boolean): {} {
+  return Object.entries(object)
+    .reduce(
+      (acc, [k, v]) => pred(k)
+        ? { ...acc, [k]: v }
+        : acc,
+      {},
+    );
+}