1  'use strict';
 2  const {PassThrough} = require('stream');
 3  
 4  module.exports = options => {
 5  	options = Object.assign({}, options);
 6  
 7  	const {array} = options;
 8  	let {encoding} = options;
 9  	const buffer = encoding === 'buffer';
10  	let objectMode = false;
11  
12  	if (array) {
13  		objectMode = !(encoding || buffer);
14  	} else {
15  		encoding = encoding || 'utf8';
16  	}
17  
18  	if (buffer) {
19  		encoding = null;
20  	}
21  
22  	let len = 0;
23  	const ret = [];
24  	const stream = new PassThrough({objectMode});
25  
26  	if (encoding) {
27  		stream.setEncoding(encoding);
28  	}
29  
30  	stream.on('data', chunk => {
31  		ret.push(chunk);
32  
33  		if (objectMode) {
34  			len = ret.length;
35  		} else {
36  			len += chunk.length;
37  		}
38  	});
39  
40  	stream.getBufferedValue = () => {
41  		if (array) {
42  			return ret;
43  		}
44  
45  		return buffer ? Buffer.concat(ret, len) : ret.join('');
46  	};
47  
48  	stream.getBufferedLength = () => len;
49  
50  	return stream;
51  };