Merge pull request #194 from dentrado/promise-support

Handle promises
rtfeldman · Mar 8, 2017 · c5af0b6 · c5af0b6
2 parents 2f8c108 + 041ef0c
commit c5af0b6
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diff --git a/seamless-immutable.development.js b/seamless-immutable.development.js
@@ -612,9 +612,16 @@ function immutableInit(config) {
            obj instanceof File;
   }
 
+  function isPromise(obj) {
+    return typeof obj === 'object' &&
+           typeof obj.then === 'function';
+  }
+
   function Immutable(obj, options, stackRemaining) {
     if (isImmutable(obj) || isReactElement(obj) || isFileObject(obj)) {
       return obj;
+    } else if (isPromise(obj)) {
+      return obj.then(Immutable);
     } else if (Array.isArray(obj)) {
       return makeImmutableArray(obj.slice());
     } else if (obj instanceof Date) {

diff --git a/src/seamless-immutable.js b/src/seamless-immutable.js
@@ -612,9 +612,16 @@ function immutableInit(config) {
            obj instanceof File;
   }
 
+  function isPromise(obj) {
+    return typeof obj === 'object' &&
+           typeof obj.then === 'function';
+  }
+
   function Immutable(obj, options, stackRemaining) {
     if (isImmutable(obj) || isReactElement(obj) || isFileObject(obj)) {
       return obj;
+    } else if (isPromise(obj)) {
+      return obj.then(Immutable);
     } else if (Array.isArray(obj)) {
       return makeImmutableArray(obj.slice());
     } else if (obj instanceof Date) {

diff --git a/test/Immutable.spec.js b/test/Immutable.spec.js
@@ -72,6 +72,26 @@ var getTestUtils = require("./TestUtils.js");
         })
       });
 
+      it("makes the promise fulfillment value immutable, but not the promise itself", function() {
+        var promise = Promise.resolve([1,2,3]);
+        var wrappedPromise = Immutable(promise);
+
+        wrappedPromise.then(result => {
+          assert.isTrue(Immutable.isImmutable(result), 'The promise fulfillment value should be immutable');
+          assert.isFalse(Immutable.isImmutable(wrappedPromise), 'The promise itself should not be immutable');
+        });
+      });
+
+      it("doesn't wrap the promise rejection reason", function() {
+        var reason = new Error('foo');
+        var promise = Promise.reject(reason);
+        var wrappedPromise = Immutable(promise);
+
+        wrappedPromise.catch(catchedReason => {
+          assert.strictEqual(reason, catchedReason, 'The promise rejection reason should be left untouched');
+        });
+      });
+
       it("doesn't fail when a function is defined on Array.prototype", function() {
         Array.prototype.veryEvilFunction = function() {};
         Immutable([]);