feat: add json mode

Author: infodusha

README.MD

@@ -39,20 +39,29 @@ Use in your app:
 ```javascript
 console.log(CONFIG.PARAM); // Equals to VALUE or can be overriten in the env
 ```
+## JSON mode
 
+If you run the app with `--json` flag, it will return json instead of script.
+So you can use it in your app like this:
+```javascript
+fetch('config.json')
+    .then(response => response.json())
+    .then(config => console.log(config.PARAM));
+```
 
 ## CLI arguments
 
 Each argument can be passed as a flag or as a value (e.g. `--port 8080` or `--port=8080`).
 Arguments have short aliases (e.g. `-p 8080`)
 
-| Parameter  | Type      | Default  | Description                         |
-|:-----------|:----------|:---------|:------------------------------------|
-| `port`     | `string`  | `8080`   | Port where app is serverd           |
-| `file`     | `string`  | `.env`   | Env filename to read                |
-| `variable` | `string`  | `CONFIG` | Name of variable in global script   |
-| `window`   | `boolean` | `false`  | If variable should be set to window |
-| `compress` | `boolean` | `false`  | If script should be one-line        |
+| Parameter  | Type      | Default  | Description                                                       |
+|:-----------|:----------|:---------|:------------------------------------------------------------------|
+| `port`     | `string`  | `8080`   | Port where app is serverd                                         |
+| `file`     | `string`  | `.env`   | Env filename to read                                              |
+| `variable` | `string`  | `CONFIG` | Name of variable in global script                                 |
+| `window`   | `boolean` | `false`  | If variable should be set to window                               |
+| `compress` | `boolean` | `false`  | If script should be one-line                                      |
+| `json`     | `boolean` | `false`  | Response as json instead of script. (`-v` and `-w` are forbidden) |
 
 ## Contributing
 

lib/config.js

@@ -26,4 +26,9 @@ export const argsOptions = {
         short: 'c',
         default: false,
     },
+    json: {
+        type: 'boolean',
+        short: 'j',
+        default: false,
+    },
 };

lib/main.js

@@ -4,7 +4,15 @@ import http from 'node:http';
 import { argsOptions, TBD_SYMBOL } from './config.js';
 
 function getArgs() {
-    return parseArgs({ options: argsOptions }).values;
+    const { values, tokens } =  parseArgs({ options: argsOptions, tokens: true });
+    if (values.json) {
+        const hasWindow = tokens.find((token) => token.name === 'window');
+        const hasVariable = tokens.find((token) => token.name === 'variable');
+        if (hasWindow || hasVariable) {
+            throw new Error('Cannot use --json with --window or --variable');
+        }
+    }
+    return values;
 }
 
 async function getEnvFromFile(filename) {
@@ -44,19 +52,25 @@ function checkNoTBDValues(env) {
     }
 }
 
-function buildScript(env, variable, isWindow, isCompress) {
-    const json = JSON.stringify(env, undefined, isCompress ? undefined : 2);
+function buildJson(env, isCompress) {
+    return JSON.stringify(env, undefined, isCompress ? undefined : 2);
+}
+
+function buildScript(json, variable, isWindow) {
     if (isWindow) {
         return `window.${variable} = ${json};`;
     }
     return `const ${variable} = ${json};`;
 }
 
-function createRequestHandler(script) {
+function createRequestHandler(env, args) {
+    const json = buildJson(env, args.compress);
+    const contentType = args.json ? 'application/json' : 'application/javascript';
+    const content = args.json ? json : buildScript(json, args.variable, args.window);
     return (req, res) => {
         res.statusCode = 200;
-        res.setHeader('Content-Type', 'application/javascript');
-        res.end(script);
+        res.setHeader('Content-Type', contentType);
+        res.end(content);
     }
 }
 
@@ -65,8 +79,8 @@ export async function main() {
     const envFromFile = await getEnvFromFile(args.file);
     const env = overrideWithProcessValues(envFromFile);
     checkNoTBDValues(env);
-    const script = buildScript(env, args.variable, args.window, args.compress);
-    const server = http.createServer(createRequestHandler(script));
+    const handler = createRequestHandler(env, args);
+    const server = http.createServer(handler);
     server.listen(args.port, () => {
         console.log(`Server is listening on port ${args.port}`);
     });

test.js

@@ -18,7 +18,7 @@ describe('tests',   () => {
         return res;
     }
 
-    function getScript() {
+    function getResponseData() {
         const res = getResponse();
         return res.end.mock.calls[0].arguments[0];
     }
@@ -48,7 +48,7 @@ describe('tests',   () => {
         await assert.doesNotReject(main);
         assert.strictEqual(listenMock.mock.calls[0].arguments[0], '8080'); // Port
         assert.strictEqual(fs.readFile.mock.calls[0].arguments[0], '.env'); // File
-        assert.match(getScript(), /^const CONFIG = \{\n/); // Variable & Window & Compress
+        assert.match(getResponseData(), /^const CONFIG = \{\n/); // Variable & Window & Compress
     });
 
     it('Serves with correct content type',  async () => {
@@ -67,20 +67,20 @@ describe('tests',   () => {
     it('Can do compression',  async () => {
         setArgs(['-c']);
         await main();
-        assert.strictEqual(getScript(), `const CONFIG = {"FOO":"BAR"};`);
+        assert.strictEqual(getResponseData(), `const CONFIG = {"FOO":"BAR"};`);
     });
 
     it('Can set as window',  async () => {
         setArgs(['-w']);
         await main();
-        assert.match(getScript(), /^window\.CONFIG = \{\n/);
+        assert.match(getResponseData(), /^window\.CONFIG = \{\n/);
     });
 
     it('Overrides with process values',  async () => {
         process.env.FOO = 'BAZ';
         setArgs(['-c']);
         await main();
-        assert.strictEqual(getScript(), `const CONFIG = {"FOO":"BAZ"};`);
+        assert.strictEqual(getResponseData(), `const CONFIG = {"FOO":"BAZ"};`);
     });
 
     it('Throws if TBD values',  async () => {
@@ -95,6 +95,37 @@ describe('tests',   () => {
         process.env.HI = 'HELLO';
         setArgs(['-c']);
         await main();
-        assert.strictEqual(getScript(), `const CONFIG = {"FOO":"BAR"};`);
+        assert.strictEqual(getResponseData(), `const CONFIG = {"FOO":"BAR"};`);
+    });
+
+    describe('json mode',   () => {
+        it('Serves json',   async () => {
+            setArgs(['-j', '-c']);
+            await main();
+            assert.strictEqual(getResponseData(), `{"FOO":"BAR"}`);
+        });
+
+        it('Serves with correct content type',   async () => {
+            setArgs(['-j']);
+            await main();
+            assert.strictEqual(getResponse().setHeader.mock.calls[0].arguments[0], 'Content-Type');
+            assert.strictEqual(getResponse().setHeader.mock.calls[0].arguments[1], 'application/json');
+        });
+
+        it('Throws when --window',   async () => {
+            setArgs(['-j', '-w']);
+            await assert.rejects(main, {
+                name: 'Error',
+                message: `Cannot use --json with --window or --variable`,
+            });
+        });
+
+        it('Throws when --variable',   async () => {
+            setArgs(['-j', '-v', 'key']);
+            await assert.rejects(main, {
+                name: 'Error',
+                message: `Cannot use --json with --window or --variable`,
+            });
+        });
     });
 });