docs and tests for trigger filters

6 files changed, 205 insertions, 20 deletions

diff --git a/src/htmx.js b/src/htmx.js
index a5fa83c5..178ea9e0 100644
--- a/src/htmx.js
+++ b/src/htmx.js
@@ -688,7 +688,7 @@ return (function () {
             if (tokens[0] === '[') {
                 tokens.shift();
                 var bracketCount = 1;
-                var conditional = "(function(" + paramName + "){ return (";
+                var conditionalSource = "(function(" + paramName + "){ return (";
                 var last = null;
                 while (tokens.length > 0) {
                     var token = tokens[0];
@@ -696,23 +696,26 @@ return (function () {
                         bracketCount--;
                         if (bracketCount === 0) {
                             if (last === null) {
-                                conditional = conditional + "true";
+                                conditionalSource = conditionalSource + "true";
                             }
                             tokens.shift();
-                            conditional += ")})";
+                            conditionalSource += ")})";
                             try {
-                                return eval(conditional);
+                                var conditionFunction = eval(conditionalSource);
+                                conditionFunction.source = conditionalSource;
+                                return conditionFunction;
                             } catch (e) {
-                                triggerErrorEvent(getDocument(), "htmx:syntax:error", {error:e})
+                                triggerErrorEvent(getDocument().body, "htmx:syntax:error", {error:e, source:conditionalSource})
+                                return null;
                             }
                         }
                     } else if (token === "[") {
                         bracketCount++;
                     }
                     if (isPossibleRelativeReference(token, last, paramName)) {
-                            conditional += "((" + paramName + "." + token + ") ? (" + paramName + "." + token + ") : (window." + token + "))";
+                            conditionalSource += "((" + paramName + "." + token + ") ? (" + paramName + "." + token + ") : (window." + token + "))";
                     } else {
-                        conditional = conditional + token;
+                        conditionalSource = conditionalSource + token;
                     }
                     last = tokens.shift();
                 }
@@ -746,7 +749,7 @@ return (function () {
                             triggerSpecs.push({trigger: 'sse', sseEvent: trigger.substr(4)});
                         } else {
                             var triggerSpec = {trigger: trigger};
-                            var eventFilter = maybeGenerateConditional(tokens, "evt");
+                            var eventFilter = maybeGenerateConditional(tokens, "event");
                             if (eventFilter) {
                                 triggerSpec.eventFilter = eventFilter;
                             }
@@ -836,10 +839,22 @@ return (function () {
             return getInternalData(elt).boosted && elt.tagName === "A" && evt.type === "click" && evt.ctrlKey;
         }
 
+        function maybeFilterEvent(triggerSpec, evt) {
+            var eventFilter = triggerSpec.eventFilter;
+            if(eventFilter){
+                try {
+                    return eventFilter(evt) !== true;
+                } catch(e) {
+                    triggerErrorEvent(getDocument().body, "htmx:eventFilter:error", {error: e, source:eventFilter.source});
+                    return true;
+                }
+            }
+            return false;
+        }
+
         function addEventListener(elt, verb, path, nodeData, triggerSpec, explicitCancel) {
             var eventListener = function (evt) {
-                if (triggerSpec.eventFilter &&
-                    triggerSpec.eventFilter(evt) !== true) {
+                if (maybeFilterEvent(triggerSpec, evt)) {
                     return;
                 }
                 if (ignoreBoostedAnchorCtrlClick(elt, evt)) {
diff --git a/test/attributes/hx-push-url.js b/test/attributes/hx-push-url.js
index 604a6d3c..80f5f366 100644
--- a/test/attributes/hx-push-url.js
+++ b/test/attributes/hx-push-url.js
@@ -37,7 +37,6 @@ describe("hx-push-url attribute", function() {
         this.server.respond();
         getWorkArea().textContent.should.equal("second")
         var cache = JSON.parse(localStorage.getItem(HTMX_HISTORY_CACHE_NAME));
-        console.log(cache);
         cache.length.should.equal(2);
         cache[1].url.should.equal("/abc123");
     });
@@ -193,7 +192,6 @@ describe("hx-push-url attribute", function() {
         for (var i = 0; i < 20; i++) {
             bigContent += bigContent;
         }
-        console.log(bigContent.length);
         try {
             localStorage.removeItem("htmx-history-cache");
             htmx._("saveToHistoryCache")("/dummy", bigContent, "Foo", 0);
diff --git a/test/attributes/hx-trigger.js b/test/attributes/hx-trigger.js
index 8752f864..25431301 100644
--- a/test/attributes/hx-trigger.js
+++ b/test/attributes/hx-trigger.js
@@ -152,7 +152,7 @@ describe("hx-trigger attribute", function(){
         spec.should.deep.equal([{trigger: 'change'}]);
     })
 
-    it('filters properly with filter spec', function(){
+    it('filters properly with false filter spec', function(){
         this.server.respondWith("GET", "/test", "Called!");
         var form = make('<form hx-get="/test" hx-trigger="evt[foo]">Not Called</form>');
         form.click();
@@ -161,10 +161,135 @@ describe("hx-trigger attribute", function(){
         form.dispatchEvent(event);
         this.server.respond();
         form.innerHTML.should.equal("Not Called");
+    })
+
+    it('filters properly with true filter spec', function(){
+        this.server.respondWith("GET", "/test", "Called!");
+        var form = make('<form hx-get="/test" hx-trigger="evt[foo]">Not Called</form>');
+        form.click();
+        form.innerHTML.should.equal("Not Called");
+        var event = htmx._("makeEvent")('evt');
         event.foo = true;
         form.dispatchEvent(event);
         this.server.respond();
         form.innerHTML.should.equal("Called!");
     })
 
+    it('filters properly compound filter spec', function(){
+        this.server.respondWith("GET", "/test", "Called!");
+        var div = make('<div hx-get="/test" hx-trigger="evt[foo&&bar]">Not Called</div>');
+        var event = htmx._("makeEvent")('evt');
+        event.foo = true;
+        div.dispatchEvent(event);
+        this.server.respond();
+        div.innerHTML.should.equal("Not Called");
+        event.bar = true;
+        div.dispatchEvent(event);
+        this.server.respond();
+        div.innerHTML.should.equal("Called!");
+    })
+
+    it('can refer to target element in condition', function(){
+        this.server.respondWith("GET", "/test", "Called!");
+        var div = make('<div hx-get="/test" hx-trigger="evt[target.classList.contains(\'doIt\')]">Not Called</div>');
+        var event = htmx._("makeEvent")('evt');
+        div.dispatchEvent(event);
+        this.server.respond();
+        div.innerHTML.should.equal("Not Called");
+        div.classList.add("doIt");
+        div.dispatchEvent(event);
+        this.server.respond();
+        div.innerHTML.should.equal("Called!");
+    })
+
+    it('negative condition', function(){
+        this.server.respondWith("GET", "/test", "Called!");
+        var div = make('<div hx-get="/test" hx-trigger="evt[!target.classList.contains(\'disabled\')]">Not Called</div>');
+        div.classList.add("disabled");
+        var event = htmx._("makeEvent")('evt');
+        div.dispatchEvent(event);
+        this.server.respond();
+        div.innerHTML.should.equal("Not Called");
+        div.classList.remove("disabled");
+        div.dispatchEvent(event);
+        this.server.respond();
+        div.innerHTML.should.equal("Called!");
+    })
+
+    it('global function call works', function(){
+        window.globalFun = function(evt) {
+            return evt.bar;
+        }
+        try {
+            this.server.respondWith("GET", "/test", "Called!");
+            var div = make('<div hx-get="/test" hx-trigger="evt[globalFun(event)]">Not Called</div>');
+            var event = htmx._("makeEvent")('evt');
+            event.bar = false;
+            div.dispatchEvent(event);
+            this.server.respond();
+            div.innerHTML.should.equal("Not Called");
+            event.bar = true;
+            div.dispatchEvent(event);
+            this.server.respond();
+            div.innerHTML.should.equal("Called!");
+        } finally {
+            delete window.globalFun;
+        }
+    })
+
+    it('global property event filter works', function(){
+        window.foo =  {
+            bar:false
+        }
+        try {
+            this.server.respondWith("GET", "/test", "Called!");
+            var div = make('<div hx-get="/test" hx-trigger="evt[foo.bar]">Not Called</div>');
+            var event = htmx._("makeEvent")('evt');
+            div.dispatchEvent(event);
+            this.server.respond();
+            div.innerHTML.should.equal("Not Called");
+            foo.bar = true;
+            div.dispatchEvent(event);
+            this.server.respond();
+            div.innerHTML.should.equal("Called!");
+        } finally {
+            delete window.foo;
+        }
+    })
+
+    it('global variable filter works', function(){
+        try {
+            this.server.respondWith("GET", "/test", "Called!");
+            var div = make('<div hx-get="/test" hx-trigger="evt[foo]">Not Called</div>');
+            var event = htmx._("makeEvent")('evt');
+            div.dispatchEvent(event);
+            this.server.respond();
+            div.innerHTML.should.equal("Not Called");
+            foo = true;
+            div.dispatchEvent(event);
+            this.server.respond();
+            div.innerHTML.should.equal("Called!");
+        } finally {
+            delete window.foo;
+        }
+    })
+
+    it('bad condition issues error', function(){
+        this.server.respondWith("GET", "/test", "Called!");
+        var div = make('<div hx-get="/test" hx-trigger="evt[a.b]">Not Called</div>');
+        var errorEvent = null;
+        var handler = htmx.on("htmx:eventFilter:error", function (event) {
+            errorEvent = event;
+        });
+        try {
+            var event = htmx._("makeEvent")('evt');
+            div.dispatchEvent(event);
+            should.not.equal(null, errorEvent);
+            should.not.equal(null, errorEvent.detail.source);
+            console.log(errorEvent.detail.source);
+        } finally {
+            htmx.off("htmx:eventFilter:error", handler);
+        }
+})
+
 })
diff --git a/test/core/tokenizer.js b/test/core/tokenizer.js
index aad583a9..30dce2fb 100644
--- a/test/core/tokenizer.js
+++ b/test/core/tokenizer.js
@@ -35,11 +35,11 @@ describe("Core htmx tokenizer tests", function(){
     {
         var tokens = tokenize("[code==4||(code==5&&foo==true)]");
         var conditional = htmx._("maybeGenerateConditional")(tokens);
-        console.log(conditional);
         var func = eval(conditional);
-        console.log(func({code: 5, foo: true}));
-        console.log(func({code: 4, foo: false}));
-        console.log(func({code: 3, foo: false}));
+        func({code: 5, foo: true}).should.equal(true);
+        func({code: 5, foo: false}).should.equal(false);
+        func({code: 4, foo: false}).should.equal(true);
+        func({code: 3, foo: true}).should.equal(false);
     });
 
 
diff --git a/www/attributes/hx-trigger.md b/www/attributes/hx-trigger.md
index 6400c930..00012956 100644
--- a/www/attributes/hx-trigger.md
+++ b/www/attributes/hx-trigger.md
@@ -8,7 +8,7 @@ title: </> htmx - hx-trigger
 The `hx-trigger` attribute allows you to specify what triggers an AJAX request.  A trigger
 value can be one of the following:
 
-* An event name (e.g. "click" or "my-custom-event") followed by a set of event modifiers
+* An event name (e.g. "click" or "my-custom-event") followed by an event filter and a set of event modifiers
 * A polling definition of the form `every <timing declaration>`
 * A comma-separated list of such events
 
@@ -20,6 +20,35 @@ A standard event, such as `click` can be specified as the trigger like so:
 <div hx-get="/clicked" hx-trigger="click">Click Me</div>
 ```
 
+#### Standard Event Filters
+
+Events can be filtered by enclosing a boolean javascript expression in square brackets after the event name.  If
+this expression evaluates to `true` the event will be triggered, otherwise it will be ignored.
+
+```html
+<div hx-get="/clicked" hx-trigger="click[ctrlKey]">Control Click Me</div>
+```
+
+This event will trigger if a click event is triggered with the `event.ctrlKey` property set to true.
+
+Conditions can also refer to global functions or state
+
+```html
+<div hx-get="/clicked" hx-trigger="click[checkGlobalState()]">Control Click Me</div>
+```
+
+And can also be combined using the standard javascript syntax
+
+```html
+<div hx-get="/clicked" hx-trigger="click[ctrlKey&&shfitKey]">Control-Shift Click Me</div>
+```
+
+Note that all symbols used in the expression will be resolved first against the triggering event, and then next
+against the global namespace, so `myEvent[foo]` will first look for a property named `foo` on the event, then look
+for a global symbol with the name `foo`
+
+#### Standard Event Modifiers
+
 Standard events can also have modifiers that change how they behave.  The modifiers are:
 
 * `once` - the event will only trigger once (e.g. the first click)
diff --git a/www/docs.md b/www/docs.md
index 5af7dd61..8433eb55 100644
--- a/www/docs.md
+++ b/www/docs.md
@@ -13,6 +13,8 @@ title: </> htmx - high power tools for html
 * [installing](#installing)
 * [ajax](#ajax)
   * [triggers](#triggers)
+    * [trigger filters](#trigger-filters)
+    * [trigger modifiers](#trigger-modifiers)
     * [special events](#special-events)
     * [polling](#polling)
     * [load polling](#load_polling)
@@ -143,7 +145,23 @@ Here is a `div` that posts to `/mouse_entered` when a mouse enters it:
    </div>
 ```
 
-If you want a request to only happen once, you can use the `once` modifier for the trigger:
+#### <a name="trigger-filters"></a> [Trigger Filters](#trigger-filters)
+
+You may also apply trigger filters by using square brackets after the event name, enclosing a javascript expression that
+will be evaluated.  If the expression evaluates to `true` the event will trigger, otherwise it will not.
+
+Here is an example that triggers only on a Control-Click of the element
+
+```html
+<div hx-get="/clicked" hx-trigger="click[ctrlKey]">Control Click Me</div>
+```
+
+Properties like `ctrlKey` will be resolved against the triggering event first, then the global scope.
+
+#### <a name="trigger-modifiers"></a> [Trigger Modifiers](#trigger-modifiers)
+
+A trigger can also have a few additional modifiers that change its behavior.  For example, if you want a request to only
+ happen once, you can use the `once` modifier for the trigger:
 
 ```html
    <div hx-post="/mouse_entered" hx-trigger="mouseenter once">
@@ -151,7 +169,7 @@ If you want a request to only happen once, you can use the `once` modifier for t
    </div>
 ```
 
-There are few other modifiers you can use for trigger:
+Other modifiers you can use for triggers are:
 
 * `changed` - only issue a request if the value of the element has changed
 *  `delay:<time interval>` - wait the given amount of time (e.g. `1s`) before