Add Env class

src/env.ts

@@ -0,0 +1,27 @@
+import _ from "lodash";
+
+export class Env {
+    private static environment: string | undefined = process.env.NODE_ENV;
+
+    static instance(): Env {
+        if (_.isUndefined(this.environment)) {
+            this.environment = "development";
+        }
+
+        return new Env();
+    }
+
+    set(environment?: string): Env {
+        Env.environment = environment;
+
+        return Env.instance();
+    }
+
+    get(): string {
+        return Env.environment!;
+    }
+
+    is(environment: string): boolean {
+        return this.get() === environment;
+    }
+}

tests/env.test.ts

@@ -0,0 +1,30 @@
+import { describe, expect, test } from "vitest";
+import { Env } from "../src/env";
+
+describe("env", () => {
+    test("env correctly uses NODE_ENV", () => {
+        const nodeEnv = process.env.NODE_ENV!;
+        const env = Env.instance();
+
+        expect(env.get()).toBe(nodeEnv);
+        expect(env.is(nodeEnv)).toBe(true);
+        expect(env.is("staging")).toBe(false);
+    });
+
+    test("env uses the fallback to NODE_ENV", () => {
+        const env = Env.instance().set(undefined);
+
+        expect(env.get()).toBe("development");
+        expect(env.is("development")).toBe(true);
+    });
+
+    test("env uses the environment set to it", () => {
+        const env = Env.instance().set("production");
+
+        expect(env.get()).toBe("production");
+        expect(env.is("production")).toBe(true);
+
+        env.set("development");
+        expect(env.is("production")).toBe(false);
+    });
+});