alphanumeric.js

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'));