Feature/enum support

package.json

@@ -1,6 +1,6 @@
 {
   "name": "@yasserfedsi/envfy",
-  "version": "0.1.0",
+  "version": "0.2.0",
   "description": "A simple, type-safe environment variable validator for Node.js applications",
   "type": "module",
   "main": "./dist/index.cjs",

src/index.ts

@@ -1,2 +1,2 @@
 export { validateEnv } from "./validateEnv";
-export type { Schema, PrimitiveType } from "./validateEnv";
+export type { Schema, PrimitiveType, EnumType } from "./validateEnv";

src/validateEnv.ts

@@ -1,8 +1,15 @@
-import { parseBoolean, parseNumber, parseString } from "./validators";
+import {
+  parseBoolean,
+  parseNumber,
+  parseString,
+  parseEnum,
+} from "./validators";
 
 export type PrimitiveType = "string" | "number" | "boolean";
 
-export type Schema = Record<string, PrimitiveType>;
+export type EnumType = readonly string[];
+
+export type Schema = Record<string, PrimitiveType | EnumType>;
 
 export function validateEnv(schema: Schema) {
   const result: Record<string, unknown> = {};
@@ -16,6 +23,11 @@ export function validateEnv(schema: Schema) {
       throw new Error(`Missing environment variable: ${key}`);
     }
 
+    if (Array.isArray(rule)) {
+      result[key] = parseEnum(key, value, rule);
+      continue;
+    }
+
     switch (rule) {
       case "string":
         result[key] = parseString(value);

src/validators.ts

@@ -18,3 +18,15 @@ export function parseBoolean(key: string, value: string): boolean {
 export function parseString(value: string): string {
   return value;
 }
+
+export function parseEnum(
+  key: string,
+  value: string,
+  allowedValues: readonly string[],
+): string {
+  if (!allowedValues.includes(value)) {
+    throw new Error(`${key} must be one of: ${allowedValues.join(", ")}`);
+  }
+
+  return value;
+}

tests/validate.test.ts

@@ -41,11 +41,32 @@ describe("validateEnv", () => {
       });
     }).toThrow();
   });
+
+  test("validates enum values", () => {
+    process.env.NODE_ENV = "development";
+
+    const env = validateEnv({
+      NODE_ENV: ["development", "production", "test"],
+    });
+
+    expect(env.NODE_ENV).toBe("development");
+  });
+
+  test("throws on invalid enum", () => {
+    process.env.NODE_ENV = "staging";
+
+    expect(() =>
+      validateEnv({
+        NODE_ENV: ["development", "production", "test"],
+      }),
+    ).toThrow("NODE_ENV must be one of");
+  });
 });
 
 beforeEach(() => {
   delete process.env.NAME;
   delete process.env.PORT;
   delete process.env.DEBUG;
   delete process.env.MISSING;
+  delete process.env.NODE_ENV;
 });