Add schema valiation

+ Using zod for validation
+ Add SchemaError

package.json

@@ -31,7 +31,8 @@
     "jsonwebtoken": "^8.5.1",
     "nodemailer": "^6.7.0",
     "redis": "^3.1.2",
-    "winston": "^3.7.2"
+    "winston": "^3.7.2",
+    "zod": "^3.14.4"
   },
   "devDependencies": {
     "@types/chai": "^4.2.22",

src/Middleware/error/SchemaError.ts

@@ -0,0 +1,9 @@
+import ForwardableError from "./ForwardableError";
+
+export default class SchemaError extends ForwardableError {
+  protected __oid = "SCHEMA_ERROR";
+
+  constructor(message: string) {
+    super(400, message);
+  }
+}

src/lib/result_schema.ts

@@ -0,0 +1,65 @@
+import { Schema, z, ZodError } from "zod";
+import SchemaError from "../Middleware/error/SchemaError";
+
+// -- Schema definitions --
+
+const SchemaVersion = z.enum(["1.0"]);
+
+const TimeUnit = z.enum(["days", "hours", "minutes", "seconds", "milliseconds"]);
+
+const DurationSchema = z
+  .object({
+    type: z.literal("duration"),
+    min: z.number().int({ message: "min must be an integer (relative to smallestUnit)" }),
+    max: z.number().int({ message: "max must be an integer (relative to smallestUnit)" }),
+    smallestUnit: TimeUnit,
+    higherIsBetter: z.boolean(),
+  })
+  .refine(({ min, max }) => min < max, { message: "min must be smaller than max" });
+
+const PointSchema = z
+  .object({
+    type: z.literal("points"),
+    min: z.number(),
+    max: z.number(),
+    step: z.number(),
+    start: z.number(),
+
+    unit: z.string(),
+    unitSign: z.string(),
+
+    higherIsBetter: z.boolean(),
+  })
+  .refine(({ min, max }) => min < max, { message: "min must be smaller than max" })
+  .refine(({ min, max, start }) => min <= start && max >= start, {
+    message: "start must be larger than or equal to min and smaller than or equal to max",
+  });
+
+export type DurationSchemaT = z.infer<typeof DurationSchema>;
+export type PointSchemaT = z.infer<typeof PointSchema>;
+
+// -- Parser --
+
+export function parseSchema(schema: any): DurationSchemaT | PointSchemaT {
+  try {
+    if (schema.type === "duration") {
+      return DurationSchema.parse(schema);
+    } else if (schema.type === "points") {
+      return PointSchema.parse(schema);
+    }
+  } catch (e) {
+    if (e instanceof ZodError) {
+      const issue = e.issues.at(0);
+
+      if (issue) {
+        throw new SchemaError(`${issue.path}: ${issue.message}`);
+      }
+
+      throw new SchemaError("Unknown error occured while validating the schema");
+    }
+
+    throw e;
+  }
+
+  throw new SchemaError("type must be either 'duration' or 'points'");
+}