fix: should return default value when env is empty string (#758)

<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->

## Summary by CodeRabbit

- Refactor
- Enhanced environment variable handling to trim extra whitespace and
improve default value checks for more robust configuration processing.
  
- Tests
- Expanded test coverage to validate default behavior, type conversions,
and error handling for various environment variable scenarios.

<!-- end of auto-generated comment: release notes by coderabbit.ai -->

Author: fengmk2

app/common/EnvUtil.ts

@@ -4,8 +4,11 @@ export function env(key: string, valueType: ValueType, defaultValue: string): st
 export function env(key: string, valueType: ValueType, defaultValue: boolean): boolean;
 export function env(key: string, valueType: ValueType, defaultValue: number): number;
 export function env(key: string, valueType: ValueType, defaultValue: string | boolean | number): string | boolean | number {
-  const value = process.env[key];
-  if (value === undefined) {
+  let value = process.env[key];
+  if (typeof value === 'string') {
+    value = value.trim();
+  }
+  if (!value) {
     return defaultValue;
   }
 

test/common/EnvUtil.test.ts

@@ -0,0 +1,92 @@
+import { strict as assert } from 'node:assert';
+import { mock } from 'egg-mock/bootstrap';
+import { env } from '../../app/common/EnvUtil';
+
+describe('test/common/EnvUtil.test.ts', () => {
+  beforeEach(mock.restore);
+
+  describe('env()', () => {
+    it('should return default value if env is not set', () => {
+      assert.equal(env('TEST_ENV_STRING', 'string', 'default'), 'default');
+      assert.equal(env('TEST_ENV_BOOLEAN', 'boolean', false), false);
+      assert.equal(env('TEST_ENV_NUMBER', 'number', 0), 0);
+    });
+
+    it('should return env value if env is set to empty string', () => {
+      mock(process.env, 'TEST_ENV_STRING', '');
+      mock(process.env, 'TEST_ENV_BOOLEAN', '');
+      mock(process.env, 'TEST_ENV_NUMBER', '');
+
+      assert.equal(env('TEST_ENV_STRING', 'string', ''), '');
+      assert.equal(env('TEST_ENV_STRING', 'string', 'default string'), 'default string');
+      assert.equal(env('TEST_ENV_BOOLEAN', 'boolean', true), true);
+      assert.equal(env('TEST_ENV_BOOLEAN', 'boolean', false), false);
+      assert.equal(env('TEST_ENV_NUMBER', 'number', 3306), 3306);
+      assert.equal(env('TEST_ENV_NUMBER', 'number', 0), 0);
+      assert.equal(env('TEST_ENV_NUMBER', 'number', -123), -123);
+
+      mock(process.env, 'TEST_ENV_STRING', '    ');
+      mock(process.env, 'TEST_ENV_BOOLEAN', '  \t  ');
+      mock(process.env, 'TEST_ENV_NUMBER', '   \t\t\t  ');
+
+      assert.equal(env('TEST_ENV_STRING', 'string', ''), '');
+      assert.equal(env('TEST_ENV_STRING', 'string', 'default string'), 'default string');
+      assert.equal(env('TEST_ENV_BOOLEAN', 'boolean', true), true);
+      assert.equal(env('TEST_ENV_BOOLEAN', 'boolean', false), false);
+      assert.equal(env('TEST_ENV_NUMBER', 'number', 3306), 3306);
+      assert.equal(env('TEST_ENV_NUMBER', 'number', 0), 0);
+    });
+
+    it('should throw error if env is set to invalid value', () => {
+      mock(process.env, 'TEST_ENV_BOOLEAN', 'invalid');
+      assert.throws(() => env('TEST_ENV_BOOLEAN', 'boolean', false), /Invalid boolean value: invalid on process.env.TEST_ENV_BOOLEAN/);
+
+      mock(process.env, 'TEST_ENV_NUMBER', 'invalid');
+      assert.throws(() => env('TEST_ENV_NUMBER', 'number', 0), /Invalid number value: invalid on process.env.TEST_ENV_NUMBER/);
+
+      mock(process.env, 'TEST_ENV_NUMBER', 'abc');
+      assert.throws(() => env('TEST_ENV_NUMBER', 'number', 0), /Invalid number value: abc on process.env.TEST_ENV_NUMBER/);
+    });
+
+    it('should throw error if value type is invalid', () => {
+      mock(process.env, 'TEST_ENV_STRING', '123');
+      assert.throws(() => (env as any)('TEST_ENV_STRING', 'float', 'default'), /Invalid value type: float/);
+    });
+
+    it('should work with string value', () => {
+      mock(process.env, 'TEST_ENV_STRING', 'http://localhost:3000');
+      assert.equal(env('TEST_ENV_STRING', 'string', 'default'), 'http://localhost:3000');
+
+      mock(process.env, 'TEST_ENV_STRING', '      ');
+      assert.equal(env('TEST_ENV_STRING', 'string', 'default'), 'default');
+    });
+
+    it('should work with boolean value', () => {
+      mock(process.env, 'TEST_ENV_BOOLEAN', 'true');
+      assert.equal(env('TEST_ENV_BOOLEAN', 'boolean', false), true);
+
+      mock(process.env, 'TEST_ENV_BOOLEAN', 'false');
+      assert.equal(env('TEST_ENV_BOOLEAN', 'boolean', true), false);
+
+      mock(process.env, 'TEST_ENV_BOOLEAN', '1');
+      assert.equal(env('TEST_ENV_BOOLEAN', 'boolean', false), true);
+
+      mock(process.env, 'TEST_ENV_BOOLEAN', '0');
+      assert.equal(env('TEST_ENV_BOOLEAN', 'boolean', true), false);
+    });
+
+    it('should work with number value', () => {
+      mock(process.env, 'TEST_ENV_NUMBER', '123');
+      assert.equal(env('TEST_ENV_NUMBER', 'number', 0), 123);
+
+      mock(process.env, 'TEST_ENV_NUMBER', '-123');
+      assert.equal(env('TEST_ENV_NUMBER', 'number', 0), -123);
+
+      mock(process.env, 'TEST_ENV_NUMBER', '123.456');
+      assert.equal(env('TEST_ENV_NUMBER', 'number', 0), 123.456);
+
+      mock(process.env, 'TEST_ENV_NUMBER', '0');
+      assert.equal(env('TEST_ENV_NUMBER', 'number', 10), 0);
+    });
+  });
+});