Add options to customize parsing/stringifying JSON

readme.md

@@ -317,6 +317,23 @@ const body = await got(url).json();
 const body = await got(url, {responseType: 'json', resolveBodyOnly: true});
 ```
 
+###### parseJson
+
+Type: `(text: string) => unknown`\
+Default: `(text) => JSON.parse(text)`
+
+Function used to parse JSON responses.
+
+Example:
+
+```js
+const Bourne = require('@hapi/bourne');
+
+const parsed = await got('https://example.com', {
+	parseJson: text => Bourne.parse(text)
+}).json();
+```
+
 ###### resolveBodyOnly
 
 Type: `boolean`\

source/as-promise/core.ts

@@ -8,7 +8,7 @@ import {
 	ParseError,
 	Response
 } from './types';
-import Request, {knownHookEvents, RequestError, Method} from '../core';
+import Request, {knownHookEvents, RequestError, Method, ParseJsonFn} from '../core';
 
 if (!knownHookEvents.includes('beforeRetry' as any)) {
 	knownHookEvents.push('beforeRetry' as any, 'afterResponse' as any);
@@ -17,7 +17,7 @@ if (!knownHookEvents.includes('beforeRetry' as any)) {
 export const knownBodyTypes = ['json', 'buffer', 'text'];
 
 // @ts-ignore The error is: Not all code paths return a value.
-export const parseBody = (response: Response, responseType: ResponseType, encoding?: string): unknown => {
+export const parseBody = (response: Response, responseType: ResponseType, parseJson: ParseJsonFn, encoding?: string): unknown => {
 	const {rawBody} = response;
 
 	try {
@@ -26,7 +26,7 @@ export const parseBody = (response: Response, responseType: ResponseType, encodi
 		}
 
 		if (responseType === 'json') {
-			return rawBody.length === 0 ? '' : JSON.parse(rawBody.toString()) as unknown;
+			return rawBody.length === 0 ? '' : parseJson(rawBody.toString());
 		}
 
 		if (responseType === 'buffer') {

source/as-promise/index.ts

@@ -87,7 +87,7 @@ export default function asPromise<T>(options: NormalizedOptions): CancelableRequ
 
 				// Parse body
 				try {
-					response.body = parseBody(response, options.responseType, options.encoding);
+					response.body = parseBody(response, options.responseType, options.parseJson, options.encoding);
 				} catch (error) {
 					// Fallback to `utf8`
 					response.body = rawBody.toString();
@@ -244,7 +244,7 @@ export default function asPromise<T>(options: NormalizedOptions): CancelableRequ
 			// Wait until downloading has ended
 			await promise;
 
-			return parseBody(globalResponse, responseType, options.encoding);
+			return parseBody(globalResponse, responseType, options.parseJson, options.encoding);
 		})();
 
 		Object.defineProperties(newPromise, Object.getOwnPropertyDescriptors(promise));

source/core/index.ts

@@ -118,6 +118,7 @@ type CacheableRequestFn = (
 ) => CacheableRequest.Emitter;
 
 type CheckServerIdentityFn = (hostname: string, certificate: DetailedPeerCertificate) => Error | void;
+export type ParseJsonFn = (text: string) => unknown;
 
 interface RealRequestOptions extends https.RequestOptions {
 	checkServerIdentity: CheckServerIdentityFn;
@@ -150,6 +151,7 @@ export interface Options extends URLOptions {
 	lookup?: CacheableLookup['lookup'];
 	headers?: Headers;
 	methodRewriting?: boolean;
+	parseJson?: ParseJsonFn;
 
 	// From `http.RequestOptions`
 	localAddress?: string;
@@ -201,6 +203,7 @@ export interface NormalizedOptions extends Options {
 	methodRewriting: boolean;
 	username: string;
 	password: string;
+	parseJson: ParseJsonFn;
 	[kRequest]: HttpRequestFunction;
 	[kIsNormalizedAlready]?: boolean;
 }
@@ -224,6 +227,7 @@ export interface Defaults {
 	allowGetBody: boolean;
 	https?: HTTPSOptions;
 	methodRewriting: boolean;
+	parseJson?: ParseJsonFn;
 
 	// Optional
 	agent?: Agents | false;

source/index.ts

@@ -110,7 +110,8 @@ const defaults: InstanceDefaults = {
 			countLimit: Infinity,
 			requestLimit: 10000,
 			stackAllItems: true
-		}
+		},
+		parseJson: (text: string) => JSON.parse(text)
 	},
 	handlers: [defaultHandler],
 	mutableDefaults: false

test/response-parse.ts

@@ -242,3 +242,12 @@ test('responseType is optional when using template', withServer, async (t, serve
 
 	t.deepEqual(body, data);
 });
+
+test('JSON response custom parser', withServer, async (t, server, got) => {
+	server.get('/', defaultHandler);
+
+	t.deepEqual((await got({
+		responseType: 'json',
+		parseJson: text => ({...JSON.parse(text), custom: 'parser'})
+	})).body, {...dog, custom: 'parser'});
+});