Merge pull request #475 from igncp/master

Refactor max iterations exception message

src/core/reaction.ts

@@ -166,7 +166,8 @@ export function runReactions() {
 	// we converge to no remaining reactions after a while.
 	while (allReactions.length > 0) {
 		if (++iterations === MAX_REACTION_ITERATIONS)
-			throw new Error("Reaction doesn't converge to a stable state. Probably there is a cycle in the reactive function: " + allReactions[0].toString());
+			throw new Error(`Reaction doesn't converge to a stable state after ${MAX_REACTION_ITERATIONS} iterations.`
+				+ ` Probably there is a cycle in the reactive function: ${allReactions[0]}`);
 		let remainingReactions = allReactions.splice(0);
 		for (let i = 0, l = remainingReactions.length; i < l; i++)
 			remainingReactions[i].runReaction();

test/reaction.js

@@ -225,7 +225,7 @@ test("#278 do not rerun if expr output doesn't change structurally", t => {
 	var values = [];
 
 	var d = reaction(mobx.asStructure(
-		() => users.map(user => user.uppername)	
+		() => users.map(user => user.uppername)
 	), newValue => {
 		values.push(newValue);
 	}, true)
@@ -245,3 +245,22 @@ test("#278 do not rerun if expr output doesn't change structurally", t => {
 	]);
 	t.end();
 })
+
+test("throws when the max iterations over reactions are done", t => {
+	var foo = mobx.observable({
+		a: 1,
+	});
+
+	mobx.autorun("bar", () => {
+		var x = foo.a;
+		foo.a = Math.random();
+	});
+
+	 t.throws(
+		() => foo.a++,
+		new RegExp("Reaction doesn't converge to a stable state after 100 iterations\\. "
+			+ "Probably there is a cycle in the reactive function: Reaction\\[bar\\]")
+	);
+	mobx.extras.resetGlobalState();
+	t.end();
+})