nodejs/test/parallel/test-child-process-stdin.js

// Copyright Joyent, Inc. and other Node contributors.
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//
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'use strict';
const common = require('../common');
const assert = require('assert');

const spawn = require('child_process').spawn;

const cat = spawn('cat');
cat.stdin.write('hello');
cat.stdin.write(' ');
cat.stdin.write('world');

assert.strictEqual(true, cat.stdin.writable);
assert.strictEqual(false, cat.stdin.readable);

cat.stdin.end();

let response = '';

cat.stdout.setEncoding('utf8');
cat.stdout.on('data', function(chunk) {
  console.log(`stdout: ${chunk}`);
  response += chunk;
});

cat.stdout.on('end', common.mustCall());

cat.stderr.on('data', common.mustNotCall());

cat.stderr.on('end', common.mustCall());

cat.on('exit', common.mustCall(function(status) {
  assert.strictEqual(0, status);
}));

cat.on('close', common.mustCall(function() {
  assert.strictEqual('hello world', response);
}));