remove promise swallowing

paldepind · Feb 1, 2018 · 3604505 · 3604505
1 parent 808aae2
commit 3604505
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Showing 3 changed files with 80 additions and 26 deletions.
diff --git a/README.md b/README.md
@@ -46,6 +46,7 @@ __Other features__
 
 * Supports the transducer protocol. You can for instance transduce streams with
   [Ramda](http://ramdajs.com/) and [transducers.js](https://github.com/jlongster/transducers.js).
+* Conforms to the fantasy land [monad](https://github.com/fantasyland/fantasy-land#monad) specification
 * [Atomic updates](#atomic-updates).
 
 ## Examples

diff --git a/lib/index.js b/lib/index.js
@@ -438,7 +438,6 @@ flyd.fromPromise = function fromPromise(p) {
   return s;
 }
 
-/* istanbul ignore next */
 flyd.flattenPromise = function flattenPromise(s) {
   return combine(function(s, self) {
     s().then(self);
@@ -671,12 +670,6 @@ function flushUpdate() {
  * @param {*} value
  */
 function updateStreamValue(s, n) {
-  /* istanbul ignore if  */
-  if (n !== undefined && n !== null && isFunction(n.then)) {
-    console.warn('flyd: Promise swallowing has been deprecated, please see https://github.com/paldepind/flyd#promises for more info');
-    n.then(s);
-    return;
-  }
   s.val = n;
   s.hasVal = true;
   if (inStream === undefined) {

diff --git a/test/index.js b/test/index.js
@@ -369,26 +369,86 @@ describe('stream', function() {
     });
   });
 
-  describe('promise swallowing', function() {
-    it('pushes result of promise down the stream', function(done) {
-      var s = flyd.fromPromise(Promise.resolve(12));
-      combine(function(s) {
-        assert.equal(s(), 12);
-        done();
-      }, [s]);
+  describe('Promises', function() {
+    describe('fromPromise', function() {
+      it('pushes result of promise down the stream', function(done) {
+        var s = flyd.fromPromise(Promise.resolve(12));
+        combine(function(s) {
+          assert.equal(s(), 12);
+          done();
+        }, [s]);
+      });
+      it('recursively unpacks promise', function(done) {
+        var s = flyd.fromPromise(new Promise(function(res) {
+          setTimeout(function() {
+            res(new Promise(function(res) {
+              setTimeout(res.bind(null, 12));
+            }));
+          }, 20);
+        }));
+        combine(function(s) {
+          assert.equal(s(), 12);
+          done();
+        }, [s]);
+      });
+
+      it('does not process out of order promises', function(done) {
+        var promises = [];
+        var delay = function(ms, val) {
+          var p = new Promise(function(res) {
+            setTimeout(function() {
+              res(val);
+            }, ms)
+          });
+          promises.push(p);
+          return p;
+        };
+
+        var s = stream();
+        var res = s.chain(function(val) {
+          return flyd.fromPromise(delay(val, val));
+        })
+          .pipe(flyd.scan(function(acc, v) {
+            return acc + v;
+          }, 0));
+        s(100)(50)(70)(200);
+
+        Promise.all(promises).then(function() {
+          assert.equal(res(), 200);
+          done();
+        });
+
+      });
     });
-    it('recursively unpacks promise', function(done) {
-      var s = flyd.fromPromise(new Promise(function(res) {
-        setTimeout(function() {
-          res(new Promise(function(res) {
-            setTimeout(res.bind(null, 12));
-          }));
-        }, 20);
-      }));
-      combine(function(s) {
-        assert.equal(s(), 12);
-        done();
-      }, [s]);
+    describe('flattenPromise', function() {
+      it('processes out of order promises', function(done) {
+        var promises = [];
+        var delay = function(ms, val) {
+          var p = new Promise(function(res) {
+            setTimeout(function() {
+              res(val);
+            }, ms)
+          });
+          promises.push(p);
+          return p;
+        };
+
+        var s = stream();
+        var res = s.map(function(val) {
+          return delay(val, val);
+        })
+          .pipe(flyd.flattenPromise)
+          .pipe(flyd.scan(function(acc, v) {
+            return acc + v;
+          }, 0));
+        s(100)(50)(70)(200);
+
+        Promise.all(promises).then(function() {
+          assert.equal(res(), 420);
+          done();
+        });
+
+      });
     });
   });