Initial commit of library

Author: developit

src/decko.js

@@ -0,0 +1,97 @@
+
+const EMPTY = {};
+const HOP = Object.prototype.hasOwnProperty;
+
+let fns = {
+	/**  let cachedFn = memoize(originalFn); */
+	memoize(fn, opt=EMPTY) {
+		let cache = opt.cache || {};
+		return function (...a) {
+			let k = String(a[0]);
+			if (opt.caseSensitive===false) k = k.toLowerCase();
+			return HOP.call(cache,k) ? cache[k] : (cache[k] = fn.apply(this, a));
+		};
+	},
+
+	/** let throttled = debounce(10, console.log); */
+	debounce(fn, opts) {
+		if (typeof opts==='function') { let p = fn; fn = opts; opts = p; }
+		let delay = opts && opts.delay || opts || 0,
+			args, timer;
+		return (...a) => {
+			args = a;
+			if (!timer) timer = setTimeout( () => {
+				fn(...args);
+				timer = args = null;
+			}, delay);
+		};
+	},
+
+	bind(target, key, { value: fn }) {
+		return {
+			configurable: true,
+			get() {
+				let value = fn.bind(this);
+				Object.defineProperty(this, key, {
+					value,
+					configurable: true,
+					writable: true
+				});
+				return value;
+			}
+		};
+	}
+}
+
+
+let memoize = multiMethod(fns.memoize),
+	debounce = multiMethod(fns.debounce),
+	bind = multiMethod((f,c)=>f.bind(c), ()=>fns.bind);
+
+export { memoize, debounce, bind };
+export default { memoize, debounce, bind };
+
+
+/** Creates a function that supports the following calling styles:
+ *	d() - returns an unconfigured decorator
+ *	d(opts) - returns a configured decorator
+ *	d(fn, opts) - returns a decorated proxy to `fn`
+ *	d(target, key, desc) - the decorator itself
+ *
+ *	@Example:
+ *		// simple identity deco:
+ *		let d = multiMethod( fn => fn );
+ *
+ *		class Foo {
+ *			@d
+ *			bar() { }
+ *
+ *			@d()
+ *			baz() { }
+ *
+ *			@d({ opts })
+ *			bat() { }
+ *
+ *			bap = d(() => {})
+ *		}
+ */
+function multiMethod(inner, deco) {
+	deco = deco || inner.decorate || decorator(inner);
+	let d = deco();
+	return (...args) => {
+		let l = args.length;
+		return (l<2 ? deco : (l>2 ? d : inner))(...args);
+	}
+}
+
+/** Returns function supports the forms:
+ *	deco(target, key, desc) -> decorate a method
+ *	deco(Fn) -> call the decorator proxy on a function
+ */
+function decorator(fn) {
+	return opt => (
+		typeof opt==='function' ? fn(opt) : (target, key, desc) => {
+			desc.value = fn(desc.value, opt);
+		}
+	);
+};