1  'use strict';
 2  const aliases = ['stdin', 'stdout', 'stderr'];
 3  
 4  const hasAlias = opts => aliases.some(alias => opts[alias] !== undefined);
 5  
 6  const normalizeStdio = opts => {
 7  	if (!opts) {
 8  		return;
 9  	}
10  
11  	const {stdio} = opts;
12  
13  	if (stdio === undefined) {
14  		return aliases.map(alias => opts[alias]);
15  	}
16  
17  	if (hasAlias(opts)) {
18  		throw new Error(`It's not possible to provide \`stdio\` in combination with one of ${aliases.map(alias => `\`${alias}\``).join(', ')}`);
19  	}
20  
21  	if (typeof stdio === 'string') {
22  		return stdio;
23  	}
24  
25  	if (!Array.isArray(stdio)) {
26  		throw new TypeError(`Expected \`stdio\` to be of type \`string\` or \`Array\`, got \`${typeof stdio}\``);
27  	}
28  
29  	const length = Math.max(stdio.length, aliases.length);
30  	return Array.from({length}, (value, index) => stdio[index]);
31  };
32  
33  module.exports = normalizeStdio;
34  
35  // `ipc` is pushed unless it is already present
36  module.exports.node = opts => {
37  	const stdio = normalizeStdio(opts);
38  
39  	if (stdio === 'ipc') {
40  		return 'ipc';
41  	}
42  
43  	if (stdio === undefined || typeof stdio === 'string') {
44  		return [stdio, stdio, stdio, 'ipc'];
45  	}
46  
47  	if (stdio.includes('ipc')) {
48  		return stdio;
49  	}
50  
51  	return [...stdio, 'ipc'];
52  };