feature: this commit introduces error and result classes for error handling

Author: https-richardy

UIs/Landing/patterns/error.ts

@@ -0,0 +1,10 @@
+export class Error {
+    public constructor(public code: string, public description: string) { }
+
+    public static readonly None = new Error("", "");
+    public static readonly Unknown = new Error("Unknown", "An unknown error has occurred.");
+
+    public static from(code: string, description: string): Error {
+        return new Error(code, description);
+    }
+}

UIs/Landing/patterns/result.ts

@@ -0,0 +1,24 @@
+import { Error } from "./error";
+
+export class Result<TData = void> {
+    public readonly isSuccess: boolean;
+    public readonly isFailure: boolean;
+
+    public readonly error: Error;
+    public readonly value?: TData;
+
+    private constructor(isSuccess: boolean, value?: TData, error: Error = Error.None) {
+        this.isSuccess = isSuccess;
+        this.isFailure = !isSuccess;
+        this.error = error;
+        this.value = value;
+    }
+
+    public static success<TData>(value: TData): Result<TData> {
+        return new Result<TData>(true, value, Error.None);
+    }
+
+    public static failure<TData>(error: Error): Result<TData> {
+        return new Result<TData>(false, undefined, error);
+    }
+}