bunch of key helpers (#74)

lib/common/keys.ts

@@ -21,25 +21,32 @@
  *
  */
 export enum KEY {
+  A = 'a',
   Alt = 'Alt',
   Backspace = 'Backspace',
   Control = 'Control',
+  D = 'd',
   Delete = 'Delete',
   Down = 'ArrowDown',
+  E = 'e',
   End = 'End',
   Enter = 'Enter',
   Esc = 'Esc',
   Escape = 'Escape',
   Home = 'Home',
   Insert = 'Insert',
   Left = 'ArrowLeft',
+  N = 'n',
   PageDown = 'PageDown',
   PageUp = 'PageUp',
   Right = 'ArrowRight',
+  S = 's',
   Shift = 'Shift',
   Space = ' ',
   Tab = 'Tab',
   Up = 'ArrowUp',
+  W = 'w',
+  Z = 'z',
 }
 
 /**
@@ -56,3 +63,77 @@ export enum KEY {
 export function isEscape(key: string): boolean {
   return key === KEY.Esc || key === KEY.Escape;
 }
+
+/**
+ * ### isAlphabetic
+ *
+ * Checks if the user has hit any alphabetic key (a - z)
+ *
+ * @param key - the key to check, typically from event.key
+ * @returns true if key is in the range of a-z
+ */
+export function isAlphabetic(key: string): boolean {
+  return key >= KEY.A && key <= KEY.Z;
+}
+
+/**
+ * ### isNumeric
+ *
+ * Checks if the user has hit any numeric key (0 - 9)
+ *
+ * @param key - the key to check, typically from event.key
+ * @returns true if key is in the range of 0 - 9
+ */
+export function isNumeric(key: string): boolean {
+  return key >= '0' && key <= '9';
+}
+
+/**
+ * ### isCardinal
+ *
+ * Checks if the user has hit any cardinal key (n s w e)
+ *
+ * @param key - the key to check, typically from event.key
+ * @returns true if key matches any cardinal n s w e
+ */
+export function isCardinal(key: string): boolean {
+  return key === KEY.N || key === KEY.S || key === KEY.W || key === KEY.E;
+}
+
+/**
+ * ### isArrow
+ *
+ * Checks if the user has hit any arrow key
+ *
+ * @param key - the key to check, typically from event.key
+ * @returns true if key matches any arrow keys
+ */
+export function isArrow(key: string): boolean {
+  return (
+    key === KEY.Up || key === KEY.Down || key === KEY.Left || key === KEY.Right
+  );
+}
+
+/**
+ * ### isWasd
+ *
+ * Checks if the user has hit any w a s d key
+ *
+ * @param key - the key to check, typically from event.key
+ * @returns true if key matches any w a s d
+ */
+export function isWasd(key: string): boolean {
+  return key === KEY.W || key === KEY.A || key === KEY.S || key === KEY.D;
+}
+
+/**
+ * ### isMovement
+ *
+ * Checks if the user has hit any movement key (w a s d and arrow keys)
+ *
+ * @param key - the key to check, typically from event.key
+ * @returns true if key matches any movement key w a s d and arrow keys
+ */
+export function isMovement(key: string): boolean {
+  return isWasd(key) || isArrow(key);
+}