Create join_and.ts

Author: Mqxx

src/format/join_and.ts

@@ -0,0 +1,33 @@
+
+/**
+ * This function takes an array of elements and returns a new string by concatenating all of the
+ * elements in this array except of the last element. The last element is concatenated with the
+ * `and` character string as a prefix.
+ * 
+ * @example
+ * ```
+ * console.log(joinAnd([1, 2, 3]))
+ * // 1,2 and 3
+ * 
+ * console.log(joinAnd(['foo', 'bar', 'baz'], ', ', ' but not '))
+ * // foo, bar but not baz
+ * ```
+ * @param elements 
+ * @param [separator=','] A string to separate each pair of adjacent elements of the array
+ * @param [and=' and '] A string prefix for concatenating the last element
+ * @returns The new concatenated string
+ */
+export default function joinAnd(
+  elements : (string | number)[],
+  separator : string = ',',
+  and : string = ' and '
+) : string {
+  if (elements.length === 0) {
+    return ''
+  }
+  if (elements.length === 1) {
+    return elements[0].toString()
+  }
+
+  return elements.slice(0, -1).join(separator) + and + elements.at(-1)
+}