child_process: add string shortcut for fork stdio

Add string shortcut option for stdio parameter.

Fixes: https://github.com/nodejs/node/issues/10793
PR-URL: https://github.com/nodejs/node/pull/10866
Reviewed-By: Sam Roberts <vieuxtech@gmail.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Brian White <mscdex@mscdex.net>

1 files changed, 17 insertions, 3 deletions

diff --git a/lib/child_process.js b/lib/child_process.js
index e9cf426b9e..b00e3829b4 100644
--- a/lib/child_process.js
+++ b/lib/child_process.js
@@ -17,6 +17,10 @@ const _validateStdio = child_process._validateStdio;
 const setupChannel = child_process.setupChannel;
 const ChildProcess = exports.ChildProcess = child_process.ChildProcess;
 
+function stdioStringToArray(option) {
+  return [option, option, option, 'ipc'];
+}
+
 exports.fork = function(modulePath /*, args, options*/) {
 
   // Get options and args arguments.
@@ -50,11 +54,21 @@ exports.fork = function(modulePath /*, args, options*/) {
 
   args = execArgv.concat([modulePath], args);
 
-  if (!Array.isArray(options.stdio)) {
+  if (typeof options.stdio === 'string') {
+    switch (options.stdio) {
+      case 'ignore':
+      case 'pipe':
+      case 'inherit':
+        options.stdio = stdioStringToArray(options.stdio);
+        break;
+      default:
+        throw new TypeError('Unknown stdio option');
+    }
+  } else if (!Array.isArray(options.stdio)) {
     // Use a separate fd=3 for the IPC channel. Inherit stdin, stdout,
     // and stderr from the parent if silent isn't set.
-    options.stdio = options.silent ? ['pipe', 'pipe', 'pipe', 'ipc'] :
-        [0, 1, 2, 'ipc'];
+    options.stdio = options.silent ? stdioStringToArray('pipe') :
+        stdioStringToArray('inherit');
   } else if (options.stdio.indexOf('ipc') === -1) {
     throw new TypeError('Forked processes must have an IPC channel');
   }