From 5b7094fb68e36c2c4af73e8a209a979ebbf32eae Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Ciro=20Santilli=20=E5=85=AD=E5=9B=9B=E4=BA=8B=E4=BB=B6=20?=
 =?UTF-8?q?=E6=B3=95=E8=BD=AE=E5=8A=9F?= <ciro.santilli@gmail.com>
Date: Sat, 12 Oct 2019 00:00:00 +0000
Subject: [PATCH] alphanumeric.js

---
 README.adoc                                |  2 +
 rootfs_overlay/lkmc/nodejs/alphanumeric.js | 50 ++++++++++++++++++++++
 2 files changed, 52 insertions(+)
 create mode 100755 rootfs_overlay/lkmc/nodejs/alphanumeric.js

diff --git a/README.adoc b/README.adoc
index 0a170fa..5673ad1 100644
--- a/README.adoc
+++ b/README.adoc
@@ -13190,6 +13190,8 @@ ERROR: package host-nodejs installs executables without proper RPATH
 
 Examples:
 
+* String
+** link:rootfs_overlay/lkmc/nodejs/alphanumeric.js[]: https://stackoverflow.com/questions/4444477/how-to-tell-if-a-string-contains-a-certain-character-in-javascript/58359106#58359106
 * `process`
 ** link:rootfs_overlay/lkmc/nodejs/command_line_arguments.js[]
 * `fs`
diff --git a/rootfs_overlay/lkmc/nodejs/alphanumeric.js b/rootfs_overlay/lkmc/nodejs/alphanumeric.js
new file mode 100755
index 0000000..a628e85
--- /dev/null
+++ b/rootfs_overlay/lkmc/nodejs/alphanumeric.js
@@ -0,0 +1,50 @@
+#!/usr/bin/env node
+
+// https://cirosantilli.com/linux-kernel-module-cheat#node-js
+
+const assert = require('assert');
+
+const char_is_alphanumeric = function(c) {
+  let code = c.codePointAt(0);
+  return (
+    // 0-9
+    (code > 47 && code < 58) ||
+    // A-Z
+    (code > 64 && code < 91) ||
+    // a-z
+    (code > 96 && code < 123)
+  )
+}
+
+const is_alphanumeric = function (str) {
+  for (let c of str) {
+    if (!char_is_alphanumeric(c)) {
+      return false;
+    }
+  }
+  return true;
+};
+
+// Arbitrarily defined as alphanumeric or '-' or '_'.
+const is_almost_alphanumeric = function (str) {
+  for (let c of str) {
+    if (
+      !char_is_alphanumeric(c) &&
+      !is_almost_alphanumeric.almost_chars.has(c)
+    ) {
+      return false;
+    }
+  }
+  return true;
+};
+is_almost_alphanumeric.almost_chars = new Set(['-', '_']);
+
+assert( is_alphanumeric('aB0'));
+assert(!is_alphanumeric('aB0_-'));
+assert(!is_alphanumeric('aB0_-*'));
+assert(!is_alphanumeric('你好'));
+
+assert( is_almost_alphanumeric('aB0'));
+assert( is_almost_alphanumeric('aB0_-'));
+assert(!is_almost_alphanumeric('aB0_-*'));
+assert(!is_almost_alphanumeric('你好'));