Run initially emitted errors in a zero-length timeout (plus tests)

web3 · Dec 19, 2019 · d21d746 · d21d746
1 parent ac880f6
commit d21d746
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Showing 2 changed files with 48 additions and 8 deletions.
diff --git a/packages/web3-core-subscriptions/src/subscription.js b/packages/web3-core-subscriptions/src/subscription.js
@@ -196,18 +196,28 @@ Subscription.prototype.subscribe = function() {
         return this;
     }
 
+    // throw error, if provider is not set
     if(!this.options.requestManager.provider) {
-        var err1 = new Error('No provider set.');
-        this.callback(err1, null, this);
-        this.emit('error', err1);
+        setTimeout(function(){
+            var err1 = new Error('No provider set.');
+            _this.callback(err1, null, _this);
+            _this.emit('error', err1);
+        },0);
+
         return this;
     }
 
     // throw error, if provider doesnt support subscriptions
     if(!this.options.requestManager.provider.on) {
-        var err2 = new Error('The current provider doesn\'t support subscriptions: '+ this.options.requestManager.provider.constructor.name);
-        this.callback(err2, null, this);
-        this.emit('error', err2);
+        setTimeout(function(){
+            var err2 = new Error(
+                'The current provider doesn\'t support subscriptions: ' +
+                _this.options.requestManager.provider.constructor.name
+            );
+            _this.callback(err2, null, _this);
+            _this.emit('error', err2);
+        },0);
+
         return this;
     }
 

diff --git a/test/eth.subscribe.ganache.js b/test/eth.subscribe.ganache.js
@@ -104,8 +104,7 @@ describe('subscription connect/reconnect', function() {
         }
     });
 
-    // Could not get the .on('error') version of this to work - maybe a race condition setting it up.
-    it('errors when the provider is not set', function(done){
+    it('errors when the provider is not set (callback)', function(done){
         web3 = new Web3();
 
         web3.eth.subscribe('newBlockHeaders', function(err, result){
@@ -114,6 +113,37 @@ describe('subscription connect/reconnect', function() {
         })
     });
 
+    it('errors when the provider is not set (.on("error"))', function(done){
+        web3 = new Web3();
+
+        web3.eth
+            .subscribe('newBlockHeaders')
+            .on("error", function(err){
+                assert(err.message.includes('No provider set'));
+                done();
+            })
+    });
+
+    it('errors when the provider does not support subscriptions (callback)', function(done){
+        web3 = new Web3('http://localhost:' + port);
+
+        web3.eth.subscribe('newBlockHeaders', function(err, result){
+            assert(err.message.includes("provider doesn't support subscriptions: HttpProvider"));
+            done();
+        });
+    });
+
+    it('errors when the provider is not set (.on("error"))', function(done){
+        web3 = new Web3('http://localhost:' + port);
+
+        web3.eth
+            .subscribe('newBlockHeaders')
+            .on("error", function(err){
+                assert(err.message.includes("provider doesn't support subscriptions: HttpProvider"));
+                done();
+            })
+    });
+
     it('errors when the `eth_subscribe` request got send, the reponse isnt returned from the node, and the connection does get closed in the mean time', async function() {
         await pify(server.close)();