1'use strict'; 2const alias = ['stdin', 'stdout', 'stderr']; 3 4const hasAlias = opts => alias.some(x => Boolean(opts[x])); 5 6module.exports = opts => { 7 if (!opts) { 8 return null; 9 } 10 11 if (opts.stdio && hasAlias(opts)) { 12 throw new Error(`It's not possible to provide \`stdio\` in combination with one of ${alias.map(x => `\`${x}\``).join(', ')}`); 13 } 14 15 if (typeof opts.stdio === 'string') { 16 return opts.stdio; 17 } 18 19 const stdio = opts.stdio || []; 20 21 if (!Array.isArray(stdio)) { 22 throw new TypeError(`Expected \`stdio\` to be of type \`string\` or \`Array\`, got \`${typeof stdio}\``); 23 } 24 25 const result = []; 26 const len = Math.max(stdio.length, alias.length); 27 28 for (let i = 0; i < len; i++) { 29 let value = null; 30 31 if (stdio[i] !== undefined) { 32 value = stdio[i]; 33 } else if (opts[alias[i]] !== undefined) { 34 value = opts[alias[i]]; 35 } 36 37 result[i] = value; 38 } 39 40 return result; 41}; 42