fixed a few quirks with some helpers (boolean truthiness) and added '…

…isMonad(..)' helper

README.md

@@ -158,4 +158,4 @@ Then open up `coverage/lcov-report/index.html` in a browser to view the report.
 
 ## License
 
-All code and documentation are (c) 2020 Kyle Simpson and released under the [MIT License](http://getify.mit-license.org/). A copy of the MIT License [is also included](LICENSE.txt).
+All code and documentation are (c) 2021 Kyle Simpson and released under the [MIT License](http://getify.mit-license.org/). A copy of the MIT License [is also included](LICENSE.txt).

package.json

@@ -1,7 +1,7 @@
 {
 	"name": "monio",
 	"description": "Async-capable IO monad for JS",
-	"version": "0.13.1",
+	"version": "0.14.0",
 	"main": "./src/index.js",
 	"scripts": {
 		"build": "node scripts/",

src/async-either.js

@@ -1,6 +1,6 @@
 "use strict";
 
-var { isPromise, } = require("./lib/util.js");
+var { isFunction, isPromise, } = require("./lib/util.js");
 var Either = require("./either.js");
 
 var brand = {};
@@ -111,7 +111,7 @@ function fromPromise(pr) {
 }
 
 function is(val) {
-	return val && typeof val._is == "function" && val._is(brand);
+	return val && isFunction(val._is) && val._is(brand);
 }
 
 function fromFoldable(m) {

src/either.js

@@ -1,5 +1,6 @@
 "use strict";
 
+var { isFunction, } = require("./lib/util.js");
 var Just = require("./just.js");
 
 var brand = {};
@@ -83,7 +84,7 @@ function LeftOrRight(val,isRight = true) {
 }
 
 function is(val) {
-	return val && typeof val._is == "function" && val._is(brand);
+	return val && isFunction(val._is) && val._is(brand);
 }
 
 function fromFoldable(m) {

src/io-event-stream.js

@@ -244,7 +244,7 @@ function pullFromStreams(streams) {
 		.map(function callIter(v,idx){
 			// stream (iterator) waiting for its
 			// next() call?
-			if (v && typeof v.next == "function") {
+			if (v && isFunction(v.next)) {
 				streams[idx] = (async function getNext(){
 					var pr = v.next();
 					try {
@@ -274,7 +274,7 @@ function pullFromStreams(streams) {
 function close(...streams) {
 	return IO(() => (
 		Promise.all(streams.map(async function closeStream(stream){
-			if (stream && typeof stream.return == "function") {
+			if (stream && isFunction(stream.return)) {
 				try {
 					return await stream.return();
 				}

src/io-helpers.js

@@ -1,6 +1,6 @@
 "use strict";
 
-var { isPromise, } = require("./lib/util.js");
+var { isFunction, isPromise, isMonad, } = require("./lib/util.js");
 var IO = require("./io.js");
 var Maybe = require("./maybe.js");
 var Either = require("./either.js");
@@ -156,10 +156,10 @@ function els(thens) {
 function iReturn(val) {
 	return IO(env => (
 		liftIO(env,val)
-		.chain(v => {
+		.map(v => {
 			var ret = { returned: v, };
 			returnedValues.add(ret);
-			return IO.of(ret);
+			return ret;
 		})
 		.run(env)
 	));
@@ -168,7 +168,7 @@ function iReturn(val) {
 function iNot(val) {
 	return IO(env => (
 		liftIO(env,val)
-		.chain(v => IO.of(!v))
+		.map(not)
 		.run(env)
 	));
 }
@@ -179,7 +179,7 @@ function wasReturned(v) {
 
 function liftIO(env,v) {
 	// monad?
-	if (v && typeof v == "object" && typeof v.chain == "function") {
+	if (isMonad(v)) {
 		// already an IO?
 		if (IO.is(v)) {
 			return v;
@@ -205,12 +205,12 @@ function liftIO(env,v) {
 			}
 		}
 	}
-	// function?
-	else if (typeof v == "function") {
+	// non-monad function?
+	else if (isFunction(v)) {
 		return liftIO(env,v(env));
 	}
 	// iterator?
-	else if (v && typeof v == "object" && typeof v.next == "function") {
+	else if (v && typeof v == "object" && isFunction(v.next)) {
 		return IO.do(v);
 	}
 	// fallback: wrap whatever value this is in an IO

src/io.js

@@ -1,6 +1,6 @@
 "use strict";
 
-var { isPromise, } = require("./lib/util.js");
+var { isFunction, isPromise, } = require("./lib/util.js");
 var Either = require("./either.js");
 
 var brand = {};
@@ -64,8 +64,8 @@ function IO(effect) {
 
 	function _inspect() {
 		return `${publicAPI[Symbol.toStringTag]}(${
-			typeof effect == "function" ? (effect.name || "anonymous function") :
-			(effect && typeof effect._inspect == "function") ? effect._inspect() :
+			isFunction(effect) ? (effect.name || "anonymous function") :
+			(effect && isFunction(effect._inspect)) ? effect._inspect() :
 			val
 		})`;
 	}
@@ -81,7 +81,7 @@ function of(v) {
 }
 
 function is(v) {
-	return v && typeof v._is == "function" && v._is(brand);
+	return v && isFunction(v._is) && v._is(brand);
 }
 
 function processNext(next,respVal,outerV,throwEither = false) {
@@ -171,16 +171,12 @@ function doEither(block) {
 
 function getIterator(block,v) {
 	return (
-		typeof block == "function" ? block(v) :
-		(block && typeof block == "object" && typeof block.next == "function") ? block :
+		isFunction(block) ? block(v) :
+		(block && typeof block == "object" && isFunction(block.next)) ? block :
 		undefined
 	);
 }
 
 function monadFlatMap(m,fn) {
-	return m[
-		"flatMap" in m ? "flatMap" :
-		"chain" in m ? "chain" :
-		"bind"
-	](fn);
+	return getMonadFlatMap(m).call(m,fn);
 }

src/just.js

@@ -1,5 +1,7 @@
 "use strict";
 
+var { isFunction, } = require("./lib/util.js");
+
 var brand = {};
 
 module.exports = Object.assign(Just,{
@@ -44,8 +46,8 @@ function Just(val) {
 		return (
 			typeof val == "string" ? `"${ val }"` :
 			typeof val == "undefined" ? "" :
-			typeof val == "function" ? (val.name || "anonymous function") :
-			val && typeof val._inspect == "function" ? val._inspect() :
+			isFunction(val) ? (val.name || "anonymous function") :
+			val && isFunction(val._inspect) ? val._inspect() :
 			Array.isArray(val) ? `[${ val.map(v => v == null ? String(v) : _serialize(v)) }]` :
 			String(val)
 		);
@@ -58,5 +60,5 @@ function Just(val) {
 }
 
 function is(val) {
-	return val && typeof val._is == "function" && val._is(brand);
+	return val && isFunction(val._is) && val._is(brand);
 }

src/lib/util.js

@@ -1,23 +1,44 @@
 "use strict";
 
 module.exports = {
+	getMonadFlatMap,
 	isFunction,
 	isPromise,
+	isMonad,
 	curry,
 };
+module.exports.getMonadFlatMap = getMonadFlatMap;
 module.exports.isFunction = isFunction;
 module.exports.isPromise = isPromise;
+module.exports.isMonad = isMonad;
 module.exports.curry = curry;
 
 
 // **************************
 
+function getMonadFlatMap(m) {
+	return m[
+		"flatMap" in m ? "flatMap" :
+		"chain" in m ? "chain" :
+		"bind"
+	];
+}
+
 function isFunction(v) {
-	return v && typeof v == "function";
+	return !!(v && typeof v == "function");
 }
 
 function isPromise(v) {
-	return v && typeof v.then == "function";
+	return !!(v && isFunction(v.then));
+}
+
+// duck-type check for monad'ness
+function isMonad(v) {
+	return !!(
+		v &&
+		(typeof v == "object" || isFunction(v)) &&
+		isFunction(getMonadFlatMap(v))
+	);
 }
 
 function curry(fn,arity = fn.length) {

src/maybe.js

@@ -1,5 +1,6 @@
 "use strict";
 
+var { isFunction, } = require("./lib/util.js");
 var Just = require("./just.js");
 var Nothing = require("./nothing.js");
 
@@ -86,7 +87,7 @@ function Maybe(val) {
 }
 
 function is(val) {
-	return val && typeof val._is == "function" && val._is(brand);
+	return val && isFunction(val._is) && val._is(brand);
 }
 
 function from(val) {

src/nothing.js

@@ -1,5 +1,7 @@
 "use strict";
 
+var { isFunction, } = require("./lib/util.js");
+
 var brand = {};
 
 module.exports = Object.assign(Nothing,{
@@ -35,7 +37,7 @@ function Nothing() {
 }
 
 function is(val) {
-	return val && typeof val._is == "function" && val._is(brand);
+	return val && isFunction(val._is) && val._is(brand);
 }
 
 // default isEmpty(), can be overidden