fix(env): ignore empty string on env fallback

BREAKING CHANGE: getEnv functions will ignore empty strings.

src/env.spec.ts

@@ -38,6 +38,14 @@ describe('env', () => {
       expect(getEnv(key, fallback)).toBe(fallback);
     });
 
+    it('should fallback to given fallback if value is empty string', () => {
+      const key = 'key';
+      const fallback = 'fallback';
+      process.env[key] = '';
+
+      expect(getEnv(key, fallback)).toBe(fallback);
+    });
+
     it('should undefined when env does not exist', () => {
       expect(getBooleanEnv('not-existed')).toBe(undefined);
     });
@@ -62,6 +70,20 @@ describe('env', () => {
       expect(getBooleanEnv('not-existed', fallback)).toBe(fallback);
     });
 
+    it('should fallback to given fallback', () => {
+      const fallback = false;
+
+      expect(getBooleanEnv('not-existed', fallback)).toBe(fallback);
+    });
+
+    it('should fallback to given fallback if env is empty string', () => {
+      const fallback = false;
+      const key = 'key';
+      process.env[key] = '';
+
+      expect(getBooleanEnv(key, fallback)).toBe(fallback);
+    });
+
     it('should throw error if env is not a json', () => {
       const key = 'key';
       process.env[key] = 'NOT-JSON';
@@ -105,6 +127,13 @@ describe('env', () => {
       expect(() => getRequiredEnv(key)).toThrowError();
     });
 
+    it('should throw if env empty string', () => {
+      const key = 'key';
+      process.env[key] = '';
+
+      expect(() => getRequiredEnv(key)).toThrowError();
+    });
+
     it('should return value if present', () => {
       const key = 'key';
       const value = 'value';

src/env.ts

@@ -1,22 +1,19 @@
-import { isBoolean, isNull } from './guards.js';
+import { isBoolean } from './guards.js';
+import { isNullOrEmpty } from './string.js';
 import type { NodeEnv } from './types.js';
-import { fallback, required } from './values.js';
+import { required } from './values.js';
+
+export type EnvKey = 'NODE_ENV';
 
 /**
  * give NODE_ENV value or given fallback value
  */
-export function getEnv<TKey extends string = string>(
-  key: TKey,
-): string | undefined;
 export function getEnv<
   TKey extends string = string,
-  TValue extends string | undefined = string,
->(key: TKey, defaultValue: TValue): TValue;
-export function getEnv<
-  TKey extends string = string,
-  TValue extends string | undefined = string,
+  TValue extends string | null | undefined = string,
 >(key: TKey, defaultValue?: TValue): TValue | undefined {
-  return fallback(process.env[key] as TValue, defaultValue);
+  const value = process.env[key] as TValue;
+  return isNullOrEmpty(value) ? defaultValue : value;
 }
 
 /**
@@ -29,12 +26,9 @@ export const getNodeEnv = <T extends string = never>(
 /**
  * returns NODE_ENV value or given fallback otherwise throws
  */
-export const getRequiredEnv = <
-  TKey extends string = string,
-  TValue extends string = string,
->(
+export const getRequiredEnv = <TKey extends string = string>(
   envKey: TKey,
-): TValue => required(getEnv(envKey) as TValue, envKey);
+): string => required(getEnv(envKey, null), envKey);
 
 /**
  * parse environment to a boolean or throw error
@@ -45,7 +39,7 @@ export function getBooleanEnv<TKey extends string = string>(
   defaultValue?: boolean,
 ): boolean | undefined {
   const value = getEnv(key);
-  if (isNull(value)) return defaultValue;
+  if (isNullOrEmpty(value)) return defaultValue;
 
   try {
     const boolean = JSON.parse(value);

src/values.ts

@@ -2,9 +2,12 @@ import { isNull } from './guards.js';
 import { isNullOrEmpty } from './string.js';
 import type { Nullish } from './types.js';
 
-export const required = <T>(value: Nullish | T, name: string = 'value'): T => {
+export const required = <T>(
+  value: Nullish | T,
+  name: string = 'value',
+): NonNullable<T> => {
   if (isNull(value)) throw Error(`${name} is required`);
-  return value;
+  return value as NonNullable<T>;
 };
 
 export const fallback = <T, U = T>(value: T, defaultValue: U): T | U =>