Require Node.js 8, add TypeScript definition (#28)

.travis.yml

@@ -2,4 +2,3 @@ language: node_js
 node_js:
   - '10'
   - '8'
-  - '6'

buffer-stream.js

@@ -2,7 +2,7 @@
 const {PassThrough: PassThroughStream} = require('stream');
 
 module.exports = options => {
-	options = Object.assign({}, options);
+	options = {...options};
 
 	const {array} = options;
 	let {encoding} = options;

index.d.ts

@@ -0,0 +1,66 @@
+/// <reference types="node"/>
+import {Stream} from 'stream';
+
+export interface Options {
+	/**
+	 * Maximum length of the returned string. If it exceeds this value before the stream ends, the promise will be rejected with a `MaxBufferError` error.
+	 *
+	 * @default Infinity
+	 */
+	readonly maxBuffer?: number;
+}
+
+export interface OptionsWithEncoding<EncodingType = BufferEncoding>
+	extends Options {
+	/**
+	 * [Encoding](https://nodejs.org/api/buffer.html#buffer_buffer) of the incoming stream.
+	 *
+	 * @default 'utf8'
+	 */
+	readonly encoding?: EncodingType;
+}
+
+declare const getStream: {
+	/**
+	 * Get the `stream` as a string.
+	 *
+	 * @returns A promise that resolves when the end event fires on the stream, indicating that there is no more data to be read. The stream is switched to flowing mode.
+	 */
+	(stream: Stream, options?: OptionsWithEncoding): Promise<string>;
+
+	/**
+	 * Get the `stream` as a buffer.
+	 *
+	 * It honors the `maxBuffer` option as above, but it refers to byte length rather than string length.
+	 */
+	buffer(stream: Stream, options?: OptionsWithEncoding): Promise<Buffer>;
+
+	/**
+	 * Get the `stream` as an array of values.
+	 *
+	 * It honors both the `maxBuffer` and `encoding` options. The behavior changes slightly based on the encoding chosen:
+	 *
+	 * - When `encoding` is unset, it assumes an [object mode stream](https://nodesource.com/blog/understanding-object-streams/) and collects values emitted from `stream` unmodified. In this case `maxBuffer` refers to the number of items in the array (not the sum of their sizes).
+	 * - When `encoding` is set to `buffer`, it collects an array of buffers. `maxBuffer` refers to the summed byte lengths of every buffer in the array.
+	 * - When `encoding` is set to anything else, it collects an array of strings. `maxBuffer` refers to the summed character lengths of every string in the array.
+	 */
+	array<StreamObjectModeType = unknown>(
+		stream: Stream,
+		options?: Options
+	): Promise<StreamObjectModeType[]>;
+	array(
+		stream: Stream,
+		options: OptionsWithEncoding<'buffer'>
+	): Promise<Buffer[]>;
+	array(
+		stream: Stream,
+		options: OptionsWithEncoding<BufferEncoding>
+	): Promise<string[]>;
+};
+
+export default getStream;
+
+export class MaxBufferError extends Error {
+	readonly name: 'MaxBufferError';
+	constructor();
+}

index.js

@@ -9,17 +9,20 @@ class MaxBufferError extends Error {
 	}
 }
 
-function getStream(inputStream, options) {
+async function getStream(inputStream, options) {
 	if (!inputStream) {
 		return Promise.reject(new Error('Expected a stream'));
 	}
 
-	options = Object.assign({maxBuffer: Infinity}, options);
+	options = {
+		maxBuffer: Infinity,
+		...options
+	};
 
 	const {maxBuffer} = options;
 
 	let stream;
-	return new Promise((resolve, reject) => {
+	await new Promise((resolve, reject) => {
 		const rejectPromise = error => {
 			if (error) { // A null check
 				error.bufferedData = stream.getBufferedValue();
@@ -42,10 +45,13 @@ function getStream(inputStream, options) {
 				rejectPromise(new MaxBufferError());
 			}
 		});
-	}).then(() => stream.getBufferedValue());
+	});
+
+	return stream.getBufferedValue();
 }
 
 module.exports = getStream;
-module.exports.buffer = (stream, options) => getStream(stream, Object.assign({}, options, {encoding: 'buffer'}));
-module.exports.array = (stream, options) => getStream(stream, Object.assign({}, options, {array: true}));
+module.exports.default = getStream;
+module.exports.buffer = (stream, options) => getStream(stream, {...options, encoding: 'buffer'});
+module.exports.array = (stream, options) => getStream(stream, {...options, array: true});
 module.exports.MaxBufferError = MaxBufferError;

index.test-d.ts

@@ -0,0 +1,27 @@
+import * as fs from 'fs';
+import {expectType} from 'tsd-check';
+import getStream, {MaxBufferError} from '.';
+
+const stream = fs.createReadStream('foo');
+
+expectType<Promise<string>>(getStream(stream));
+expectType<Promise<string>>(getStream(stream, {maxBuffer: 10}));
+expectType<Promise<string>>(getStream(stream, {encoding: 'utf8'}));
+
+expectType<Promise<Buffer>>(getStream.buffer(stream));
+expectType<Promise<Buffer>>(getStream.buffer(stream, {maxBuffer: 10}));
+expectType<Promise<Buffer>>(getStream.buffer(stream, {encoding: 'utf8'}));
+
+expectType<Promise<unknown>>(getStream.array(stream));
+expectType<Promise<{}>>(getStream.array<{}>(stream));
+expectType<Promise<unknown>>(getStream.array(stream, {maxBuffer: 10}));
+expectType<Promise<Buffer[]>>(getStream.array(stream, {encoding: 'buffer'}));
+expectType<Promise<Buffer[]>>(
+	getStream.array(stream, {maxBuffer: 10, encoding: 'buffer'})
+);
+expectType<Promise<string[]>>(getStream.array(stream, {encoding: 'utf8'}));
+expectType<Promise<string[]>>(
+	getStream.array(stream, {maxBuffer: 10, encoding: 'utf8'})
+);
+
+expectType<typeof MaxBufferError>(MaxBufferError);

package.json

@@ -10,13 +10,14 @@
 		"url": "sindresorhus.com"
 	},
 	"engines": {
-		"node": ">=6"
+		"node": ">=8"
 	},
 	"scripts": {
-		"test": "xo && ava"
+		"test": "xo && ava && tsd-check"
 	},
 	"files": [
 		"index.js",
+		"index.d.ts",
 		"buffer-stream.js"
 	],
 	"keywords": [
@@ -39,8 +40,10 @@
 		"pump": "^3.0.0"
 	},
 	"devDependencies": {
-		"ava": "^1.2.1",
+		"@types/node": "^11.10.5",
+		"ava": "^1.3.1",
 		"into-stream": "^4.0.0",
+		"tsd-check": "^0.3.0",
 		"xo": "^0.24.0"
 	}
 }