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node_modules/spawn-wrap/lib/debug.js

@@ -0,0 +1,32 @@
+'use strict';
+
+const util = require('util');
+const fs = require('fs')
+
+/**
+ * Boolean indicating if debug mode is enabled.
+ *
+ * @type {boolean}
+ */
+const IS_DEBUG = process.env.SPAWN_WRAP_DEBUG === '1'
+
+/**
+ * If debug is enabled, write message to stderr.
+ *
+ * If debug is disabled, no message is written.
+ */
+function debug(...args) {
+  if (!IS_DEBUG) {
+    return;
+  }
+
+  const prefix = `SW ${process.pid}: `
+  const data = util.format(...args).trim()
+  const message = data.split('\n').map(line => `${prefix}${line}\n`).join('')
+  fs.writeSync(2, message)
+}
+
+module.exports = {
+  IS_DEBUG,
+  debug,
+}