add getErrorMessage() helper

src/helpers/get-error-message.ts

@@ -0,0 +1,36 @@
+type ErrorWithMessage = {
+    message: string;
+};
+
+/**
+ * Converts error object to error with message. This method might be helpful to handle thrown errors.
+ *
+ * @param error Error object.
+ *
+ * @returns Message of the error.
+ */
+export const getErrorMessage = (error: unknown): string => {
+    /**
+     * Checks if error has message.
+     *
+     * @param e Error object.
+     */
+    const isErrorWithMessage = (e: unknown): e is ErrorWithMessage => (
+        typeof e === 'object'
+        && e !== null
+        && 'message' in e
+        && typeof (e as Record<string, unknown>).message === 'string'
+    );
+
+    if (isErrorWithMessage(error)) {
+        return error.message;
+    }
+
+    try {
+        return (new Error(JSON.stringify(error))).message;
+    } catch {
+        // fallback in case there's an error stringifying the error
+        // like with circular references for example.
+        return (new Error(String(error))).message;
+    }
+};

src/helpers/index.ts

@@ -24,6 +24,7 @@ export * from './string-utils';
 export * from './log-message';
 export * from './create-on-error-handler';
 export * from './get-descriptor-addon';
+export * from './get-error-message';
 export * from './get-property-in-chain';
 export * from './get-wildcard-property-in-chain';
 export * from './hit';