add a handleError() method to EffTask (#6)

package.json

@@ -1,6 +1,6 @@
 {
   "name": "phantasy",
-  "version": "0.11.1",
+  "version": "0.12.0",
   "description": "",
   "author": "Tim Kuminecz <tkuminecz@gmail.com>",
   "license": "MIT",

src/eff.js

@@ -190,12 +190,21 @@ export class EffTask<E: {}, A, X> {
 	}
 
 	/**
-	 * `andThen :: EffTask e a x ~> (a -> EffTask f b x) -> EffTask e b x`
+	 * `andThen :: EffTask e a x ~> (a -> EffTask f b x) -> EffTask (e & f) b x`
+	 *
+	 * Compose effects
 	 */
 	andThen<F: {}, B>(next: (a: A) => EffTask<F, B, X>): EffTask<E & F, B, X> {
 		return new EffTask(env => this.runEff(env).andThen(a => next(a).runEff(env)));
 	}
 
+	/**
+	 * `handleError :: EffTask e a x ~> (x -> EffTask f a y) -> Efftask (e & f) a y`
+	 */
+	handleError<F: {}, Y>(handle: (x: X) => EffTask<F, A, Y>): EffTask<E & F, A, Y> {
+		return new EffTask(env => this.runEff(env).handleError(a => handle(a).runEff(env)));
+	}
+
 	/**
 	 * `fromEff :: Eff e a -> EffTask e a x`
 	 *

src/task.js

@@ -130,10 +130,24 @@ export class Task<A, X> {
 		return new Task((succ, fail) => { promise.then(succ).catch(fail); });
 	}
 
+	/**
+	 * fromPromiseFn :: (() -> Promise a) -> Task a Error
+	 */
+	static fromPromiseFn<A>(promiseFn: () => Promise<A>): Task<A, Error> {
+		return Task.fromPromiseFunction(promiseFn);
+	}
+
 	/**
 	 * fromPromiseFunc :: (() -> Promise a) -> Task a Error
 	 */
 	static fromPromiseFunc<A>(promiseFn: () => Promise<A>): Task<A, Error> {
+		return Task.fromPromiseFunction(promiseFn);
+	}
+
+	/**
+	 * fromPromiseFunction :: (() -> Promise a) -> Task a Error
+	 */
+	static fromPromiseFunction<A>(promiseFn: () => Promise<A>): Task<A, Error> {
 		return Task.fromPromise(promiseFn());
 	}