Initial commit

2020-06-15 10:58:47 +08:00
commit 4f1dfe7564
8590 changed files with 1516878 additions and 0 deletions
@@ -0,0 +1,23 @@
+var _ = require('underscore');
+
+module.exports = {
+
+  /**
+   * Get the next available letter.
+   * @param {Array} letters e.g. ['a', 'b', 'd']
+   * @return {String} e.g. 'c'
+   */
+  next: function (letters) {
+    return _.chain(letters)
+      .sort()
+      .reduce(function (memo, letter) {
+        if (letter === memo) {
+          return String.fromCharCode(letter.charCodeAt() + 1);
+        } else {
+          return memo;
+        }
+      }, 'a')
+      .value();
+  }
+
+};