Add TypeScript definition (#16)

Co-authored-by: Sindre Sorhus <sindresorhus@gmail.com>

index.d.ts

@@ -0,0 +1,10 @@
+/// <reference types="node"/>
+import {IncomingMessage} from 'http';
+
+/**
+ * Decompress a HTTP response if needed.
+ *
+ * @param response - The HTTP incoming stream with compressed data.
+ * @returns The decompressed HTTP response stream.
+ */
+export default function decompressResponse(response: IncomingMessage): IncomingMessage;

index.js

@@ -3,7 +3,7 @@ const {PassThrough: PassThroughStream} = require('stream');
 const zlib = require('zlib');
 const mimicResponse = require('mimic-response');
 
-module.exports = response => {
+const decompressResponse = response => {
 	const contentEncoding = response.headers['content-encoding'];
 
 	if (!['gzip', 'deflate', 'br'].includes(contentEncoding)) {
@@ -34,3 +34,6 @@ module.exports = response => {
 
 	return stream;
 };
+
+module.exports = decompressResponse;
+module.exports.default = decompressResponse;

index.test-d.ts

@@ -0,0 +1,7 @@
+import * as http from 'http';
+import {expectType} from 'tsd-check';
+import decompressResponse from '.';
+
+http.get('localhost', response => {
+	expectType<http.IncomingMessage>(decompressResponse(response));
+});

package.json

@@ -13,10 +13,11 @@
 		"node": ">=8"
 	},
 	"scripts": {
-		"test": "xo && ava"
+		"test": "xo && ava && tsd-check"
 	},
 	"files": [
-		"index.js"
+		"index.js",
+		"index.d.ts"
 	],
 	"keywords": [
 		"decompress",
@@ -39,9 +40,11 @@
 		"mimic-response": "^2.0.0"
 	},
 	"devDependencies": {
-		"ava": "^1.1.0",
-		"get-stream": "^4.1.0",
+		"@types/node": "^11.10.5",
+		"ava": "^1.3.1",
+		"get-stream": "^5.0.0",
 		"pify": "^4.0.1",
+		"tsd-check": "^0.3.0",
 		"xo": "^0.24.0"
 	}
 }

readme.md

@@ -26,6 +26,19 @@ http.get('https://sindresorhus.com', response => {
 ```
 
 
+## API
+
+### decompressResponse(response)
+
+Returns the decompressed HTTP response stream.
+
+#### response
+
+Type: [`http.IncomingMessage`](https://nodejs.org/api/http.html#http_class_http_incomingmessage)
+
+The HTTP incoming stream with compressed data.
+
+
 ## License
 
 MIT © [Sindre Sorhus](https://sindresorhus.com)