1'use strict'; 2const common = require('../common'); 3const assert = require('assert'); 4const { spawn } = require('child_process'); 5 6// Check that, once a child process has ended, it’s safe to read from a pipe 7// that the child had used as input. 8// We simulate that using cat | (head -n1; ...) 9 10const p1 = spawn('cat', { stdio: ['pipe', 'pipe', 'inherit'] }); 11const p2 = spawn('head', ['-n1'], { stdio: [p1.stdout, 'pipe', 'inherit'] }); 12 13// First, write the line that gets passed through p2, making 'head' exit. 14p1.stdin.write('hello\n'); 15p2.stdout.setEncoding('utf8'); 16p2.stdout.on('data', common.mustCall((chunk) => { 17 assert.strictEqual(chunk, 'hello\n'); 18})); 19p2.on('exit', common.mustCall(() => { 20 // We can now use cat’s output, because 'head' is no longer reading from it. 21 p1.stdin.end('world\n'); 22 p1.stdout.setEncoding('utf8'); 23 p1.stdout.on('data', common.mustCall((chunk) => { 24 assert.strictEqual(chunk, 'world\n'); 25 })); 26 p1.stdout.resume(); 27})); 28