feat: added catchAllHandlerKey to handler

- can now specify a "catchall" for a handler, letting a single function attempt to handle all other values that would not get matched otherwise

packages/util/src/lib/service/handler.spec.ts

@@ -1,4 +1,4 @@
-import { Handler, makeHandler } from './handler';
+import { catchAllHandlerKey, Handler, makeHandler } from './handler';
 
 describe('handler()', () => {
 
@@ -21,7 +21,6 @@ describe('handler()', () => {
     describe('set', () => {
 
       it('should set the function on the handler for that key', () => {
-
         let wasUsed = false;
 
         const key = '1';
@@ -40,6 +39,25 @@ describe('handler()', () => {
         expect(wasUsed).toBe(true);
       });
 
+      it('should set the catch all when using the catchall key', () => {
+        let wasUsed = false;
+
+        const otherValue = 10000;
+
+        const fn = (x: number) => {
+          wasUsed = true;
+          expect(x).toBe(otherValue);
+          return true;  // result
+        };
+
+        handler.set(catchAllHandlerKey(), fn);
+        expect(wasUsed).toBe(false);
+
+        const result = handler(otherValue);
+        expect(result).toBe(true);
+        expect(wasUsed).toBe(true);
+      });
+
     });
 
     describe('bindSet', () => {

packages/util/src/lib/service/handler.ts

@@ -1,12 +1,20 @@
 import { PrimativeKey, ReadKeyFunction } from './../key';
 import { ArrayOrValue } from './../array/array';
-import { PromiseOrValue, setKeysOnMap } from '@dereekb/util';
+import { Maybe, PromiseOrValue, setKeysOnMap } from '@dereekb/util';
+
+/**
+ * Key used to signify 
+ */
+export const CATCH_ALL_HANDLE_RESULT_KEY = '__CATCH_ALL_HANDLE_RESULT_KEY__';
 
 /**
  * Whether or not the input value was handled.
  */
 export type HandleResult = boolean;
 
+export type HandlerCatchAllKey = typeof CATCH_ALL_HANDLE_RESULT_KEY;
+export type HandlerKey<K extends PrimativeKey = string> = K | HandlerCatchAllKey;
+
 /**
  * Used to perform a task on the input value.
  * 
@@ -22,7 +30,7 @@ export interface HandlerSetAccessor<T, K extends PrimativeKey = string> {
    * @param key 
    * @param handle 
    */
-  set(key: ArrayOrValue<K>, handle: HandlerFunction<T>): void;
+  set(key: ArrayOrValue<HandlerKey<K>>, handle: HandlerFunction<T>): void;
 
 }
 
@@ -40,7 +48,7 @@ export interface HandlerAccessor<T, K extends PrimativeKey = string> extends Han
    * @param key 
    * @param handle 
    */
-  bindSet(bindTo: any, key: ArrayOrValue<K>, handle: HandlerFunction<T>): void;
+  bindSet(bindTo: any, key: ArrayOrValue<HandlerKey<K>>, handle: HandlerFunction<T>): void;
 
 }
 
@@ -49,10 +57,15 @@ export type HandlerFactory<T, K extends PrimativeKey = string> = () => Handler<T
 
 export function handlerFactory<T, K extends PrimativeKey = string>(readKey: ReadKeyFunction<T, K>): HandlerFactory<T, K> {
   return () => {
+    let catchAll: Maybe<HandlerFunction<T>>;
     const map = new Map<K, HandlerFunction<T>>();
 
     const set = (key: ArrayOrValue<K>, handle: HandlerFunction<T>) => {
-      setKeysOnMap(map, key, handle);
+      if (key === CATCH_ALL_HANDLE_RESULT_KEY) {
+        catchAll = handle;
+      } else {
+        setKeysOnMap(map, key, handle);
+      }
     };
 
     const bindSet = (bindTo: any, key: ArrayOrValue<K>, handle: HandlerFunction<T>) => {
@@ -62,7 +75,7 @@ export function handlerFactory<T, K extends PrimativeKey = string>(readKey: Read
 
     const fn: Handler<T, K> = ((value: T) => {
       const key = readKey(value);
-      const handler = (key != null) ? map.get(key) : undefined;
+      const handler = ((key != null) ? map.get(key) : undefined) ?? catchAll;
       let handled: PromiseOrValue<boolean> = false;
 
       if (handler) {
@@ -83,3 +96,7 @@ export function handlerFactory<T, K extends PrimativeKey = string>(readKey: Read
 export function makeHandler<T, K extends PrimativeKey = string>(readKey: ReadKeyFunction<T, K>): Handler<T, K> {
   return handlerFactory(readKey)();
 }
+
+export function catchAllHandlerKey(): typeof CATCH_ALL_HANDLE_RESULT_KEY {
+  return CATCH_ALL_HANDLE_RESULT_KEY;
+}