fix(promises): throw TypeError from promisified function when no Promise

until now it throws less meaningful error such as "boolean is not a function" - which not make sense
to the end user

fixes #16

dist/redolent.common.js

@@ -352,6 +352,10 @@ var index = function redolent (fn, opts) {
     opts.context = this || opts.context;
     opts.args = index$2(opts.args).concat(index$4(arguments));
 
+    if (typeof opts.Promise !== 'function') {
+      throw new TypeError('redolent: no native Promise support and no opts.Promise')
+    }
+
     var promise = new opts.Promise(function (resolve, reject) {
       var called = false;
 
@@ -376,10 +380,14 @@ var index = function redolent (fn, opts) {
       }
     });
 
-    promise.___nativePromise = Boolean(index$10);
-    promise.___customPromise = !promise.___nativePromise;
-    return promise
+    return normalize(promise, index$10)
   }
 };
 
+function normalize (promise, isNativeSupported) {
+  promise.___nativePromise = Boolean(isNativeSupported);
+  promise.___customPromise = !promise.___nativePromise;
+  return promise
+}
+
 module.exports = index;

dist/redolent.es.js

@@ -350,6 +350,10 @@ var index = function redolent (fn, opts) {
     opts.context = this || opts.context;
     opts.args = index$2(opts.args).concat(index$4(arguments));
 
+    if (typeof opts.Promise !== 'function') {
+      throw new TypeError('redolent: no native Promise support and no opts.Promise')
+    }
+
     var promise = new opts.Promise(function (resolve, reject) {
       var called = false;
 
@@ -374,10 +378,14 @@ var index = function redolent (fn, opts) {
       }
     });
 
-    promise.___nativePromise = Boolean(index$10);
-    promise.___customPromise = !promise.___nativePromise;
-    return promise
+    return normalize(promise, index$10)
   }
 };
 
+function normalize (promise, isNativeSupported) {
+  promise.___nativePromise = Boolean(isNativeSupported);
+  promise.___customPromise = !promise.___nativePromise;
+  return promise
+}
+
 export default index;

index.js

@@ -82,6 +82,10 @@ module.exports = function redolent (fn, opts) {
     opts.context = this || opts.context
     opts.args = arrify(opts.args).concat(sliced(arguments))
 
+    if (typeof opts.Promise !== 'function') {
+      throw new TypeError('redolent: no native Promise support and no opts.Promise')
+    }
+
     var promise = new opts.Promise(function (resolve, reject) {
       var called = false
 
@@ -106,8 +110,12 @@ module.exports = function redolent (fn, opts) {
       }
     })
 
-    promise.___nativePromise = Boolean(Native)
-    promise.___customPromise = !promise.___nativePromise
-    return promise
+    return normalize(promise, Native)
   }
 }
+
+function normalize (promise, isNativeSupported) {
+  promise.___nativePromise = Boolean(isNativeSupported)
+  promise.___customPromise = !promise.___nativePromise
+  return promise
+}

test.js

@@ -160,14 +160,30 @@ function factory (promisify) {
   })
 }
 
+function factoryNoPromise (fn, opts) {
+  test('should throw TypeError from promisified function if no Promise', function (done) {
+    function fixture () {
+      fn(function () {
+        return 123
+      }, opts)()
+    }
+
+    test.throws(fixture, TypeError)
+    test.throws(fixture, /no native Promise support and no opts\.Promise/)
+    done()
+  })
+}
+
 if (semver.lt(process.version, '0.11.13')) {
   factory(function (fn, opts) {
     return redolent(fn, extend({
       Promise: Pinkie
     }, opts))
   })
+  factoryNoPromise(redolent)
 } else {
   factory(function (fn, opts) {
     return redolent(fn, extend({}, opts))
   })
+  factoryNoPromise(redolent, { Promise: false })
 }