feat: add withJson

main.js

@@ -36,6 +36,7 @@ export { setSessionValue } from './src/setSessionValue'
 export { STATUS_CODES } from './src/STATUS_CODES'
 export { stop } from './src/stop'
 export { toReadableStream } from './src/toReadableStream'
+export { withJson } from './src/withJson'
 export { writeBody } from './src/writeBody'
 export { writeCompressibleBody } from './src/writeCompressibleBody'
 export { writeContentEncoding } from './src/writeContentEncoding'

src/withJson.js

@@ -0,0 +1,10 @@
+export function withJson(value, options = null) {
+  return {
+    ...options,
+    headers: {
+      ...(options != null && options.headers != null ? options.headers : null),
+      'Content-Type': 'application/json',
+    },
+    body: value,
+  }
+}