Merge pull request #1351 from stealjs/reloader

reload(callback) syntax now returns an error
stealjs · Mar 6, 2018 · fde0ab3 · fde0ab3
2 parents 53f54ea + 0255624
commit fde0ab3
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diff --git a/docs/module-live-reload.md b/docs/module-live-reload.md
@@ -18,7 +18,7 @@ reload(function(){
 });
 ```
 
-@param {Function} callback A function to be called after a reload cycle is complete.
+@param {function(err)} callback A function to be called after a reload cycle is complete.
 
 @signature `reload(moduleName, callback)`
 
@@ -102,5 +102,20 @@ render();
 reload(function(){
 	render();
 });
+```
+
+## Error handling
+
+The *live-reload* module will include an [Error](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Error) if there is any error that occurs when reloading the module tree.
+
+```js
+import reload from "live-reload";
 
+reload(function(err) {
+  if(err) {
+    displayErrorMessage(err);
+  } else {
+    // Do whatever you normally do on a reload.
+  }
+});
 ```
diff --git a/ext/live-reload.js b/ext/live-reload.js
@@ -210,10 +210,16 @@ function addLiveReload(loader) {
 		for(var i = 0, len = moduleNames.length; i < len; i++) {
 			promises.push(reload(moduleNames[i]));
 		}
-		return Promise.all(promises).then(function(){
+		return Promise.all(promises)
+		.then(function(){
 			var e = loader._liveEmitter;
 			loader._inLiveReloadCycle = false;
 			e.emit("!cycleComplete");
+		}, function(err){
+			var error = err.originalErr || err;
+			var e = loader._liveEmitter;
+			loader._inLiveReloadCycle = false;
+			e.emit("!cycleComplete", error);
 		});
 	}
 
@@ -240,11 +246,14 @@ function addLiveReload(loader) {
 		return Promise.all(imports).then(function(){
 			// Remove any newly orphaned modules before declaring the cycle complete.
 			removeOrphans(moduleName, currentDeps);
-		}, function(){
+		}, function(err){
 			// There was an error re-importing modules
 			// Workers don't have a location and no way to refresh the page.
-			if(loader.global.location && loader.global.location.reload) {
+			var canReload = loader.global.location && loader.global.location.reload;
+			if(canReload && loader.liveReloadReload !== false) {
 				loader.global.location.reload();
+			} else {
+				return Promise.reject(err);
 			}
 		});
 	}

diff --git a/test/live_reload/unit.js b/test/live_reload/unit.js
@@ -1,5 +1,6 @@
 var reloader = require("live-reload");
 var loader = require("@loader");
+loader.liveReloadReload = false;
 
 QUnit.module("Unit tests", {
 	beforeEach: function(){
@@ -86,6 +87,38 @@ QUnit.test("Can be cloned", function(assert){
 	.then(done, done);
 });
 
+QUnit.test("Returns an error when there is an error", function(assert){
+	var done = assert.async();
+	var loaded = false;
+
+	var fetch = loader.fetch;
+	loader.fetch = function(load){
+		if(load.name === "oops") {
+			if(loaded) {
+				return Promise.resolve("module.exports = {}; oops 'bad';");
+			} else {
+				return Promise.resolve("module.exports = {};");
+			}
+		}
+		return fetch.apply(this, arguments);
+	};
+
+	return loader.import("oops")
+	.then(function(){
+		loaded = true;
+		return loader.import("live-reload", { name: "error-in-tree" })
+	})
+	.then(function(reload){
+		reload(function(err){
+			assert.ok(err instanceof Error, "Got an error");
+			loader.fetch = fetch;
+			done();
+		});
+
+		reloader("oops");
+	});
+});
+
 QUnit.module("reload.isReloading");
 
 QUnit.test("is false by default", function(assert){