node/test/parallel/test-child-process-fork.js

// Copyright Joyent, Inc. and other Node contributors.
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//
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// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
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'use strict';
const common = require('../common');
const assert = require('assert');
const fork = require('child_process').fork;
const args = ['foo', 'bar'];

const n = fork(`${common.fixturesDir}/child-process-spawn-node.js`, args);

assert.strictEqual(n.channel, n._channel);
assert.deepStrictEqual(args, ['foo', 'bar']);

n.on('message', function(m) {
  console.log('PARENT got message:', m);
  assert.ok(m.foo);
});

// https://github.com/joyent/node/issues/2355 - JSON.stringify(undefined)
// returns "undefined" but JSON.parse() cannot parse that...
assert.throws(function() { n.send(undefined); }, TypeError);
assert.throws(function() { n.send(); }, TypeError);

n.send({ hello: 'world' });

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