From 7a53bfcfbeba825fcaf89f4e52493dc8ec5f17c2 Mon Sep 17 00:00:00 2001
From: C-3PO <c-3po@jedipedia.net>
Date: Thu, 25 Oct 2018 07:23:36 +0200
Subject: [PATCH] =?UTF-8?q?=E2=99=BB=EF=B8=8F=20Remove=20nested=20try-catc?=
 =?UTF-8?q?h?=
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---
 src/interfaces/IOption.ts        |  6 +++---
 src/verifyAndStoreOptionValue.ts | 34 ++++++++++++++++----------------
 2 files changed, 20 insertions(+), 20 deletions(-)

diff --git a/src/interfaces/IOption.ts b/src/interfaces/IOption.ts
index 368b116..f09ada2 100644
--- a/src/interfaces/IOption.ts
+++ b/src/interfaces/IOption.ts
@@ -8,8 +8,8 @@ export default interface IOption {
   short?: string;
   /** A human readable description of this option, for display in the usage message. Not displayed if `undefined` or an empty string. */
   description?: string;
-  /** A function that verifies if the given value is a valid value for this option. If set to `undefined`, any value is accepted for this option. */
+  /** A function that verifies if the given value is a valid value for this option. If the function is missing, any value is accepted for this option. */
   verify?: (value: string) => boolean;
-  /** A function returning a custom error message that is shown if the verify function returns false. If the function is `undefined`, or it returns `undefined` or an empty string, a default error message is shown instead. */
-  message?: (value: string) => string;
+  /** A function returning a custom error message that is shown if the verify function returns false. If the function is missing, or it returns `undefined` or an empty string, a default error message is shown instead. */
+  message?: (value: string) => (string | undefined);
 }
diff --git a/src/verifyAndStoreOptionValue.ts b/src/verifyAndStoreOptionValue.ts
index d009275..b69f127 100644
--- a/src/verifyAndStoreOptionValue.ts
+++ b/src/verifyAndStoreOptionValue.ts
@@ -1,11 +1,20 @@
 import IOption from './interfaces/IOption';
 import IState from './interfaces/IState';
 
+/** Calls the given function, and in case of an error, uses the given function to provide a custom description for the error message. */
+function execWithCustomError(func: (...args: any[]) => any, showError: (error: Error) => string) {
+  try {
+    return func();
+  } catch (error) {
+    throw new Error(showError(error));
+  }
+}
+
 export default function verifyAndStoreOptionValue({
   option,
   value,
-  verify,
-  message,
+  verify = () => true,
+  message = () => '',
   outputArgs,
   requiredOptions,
 }: {
@@ -17,22 +26,13 @@ export default function verifyAndStoreOptionValue({
   requiredOptions: IState['requiredOptions'],
 }) {
   //Verify value for correctness
-  try {
-    if (verify !== undefined && !verify(value)) {
-      if (message !== undefined) {
-        try {
-          const customMessage = message(value);
-          if (customMessage !== undefined && customMessage !== '') {
-            throw new Error(customMessage);
-          }
-        } catch (error) {
-          throw new Error(`Invalid value set for option "${option}": "${value}". Could not show custom error message: ${String(error)}`);
-        }
-      }
-      throw new Error(`Invalid value set for option "${option}": "${value}".`);
+  const verifyValue = execWithCustomError(verify.bind(null, value), (error) => `Invalid value set for option "${option}", the validation of "${value}" failed: ${String(error)}`);
+  if (verifyValue !== true) {
+    const customMessage = execWithCustomError(message.bind(null, value), (error) => `Invalid value set for option "${option}": "${value}". Could not create custom error message: ${String(error)}`);
+    if (customMessage !== undefined && customMessage !== '') {
+      throw new Error(customMessage);
     }
-  } catch (error) {
-    throw new Error(`Invalid value set for option "${option}", the validation of "${value}" failed: ${String(error)}`);
+    throw new Error(`Invalid value set for option "${option}": "${value}".`);
   }
 
   //Remember the value, and if it is a required argument, mark that we have encountered it