Implement basic error tolerance

Author: dead-claudia

render/render.js

@@ -10,16 +10,24 @@ module.exports = function($window) {
 		math: "http://www.w3.org/1998/Math/MathML"
 	}
 
+	var hookError, hookThrown
 	var onevent
 	function setEventCallback(callback) {return onevent = callback}
 
 	function getNameSpace(vnode) {
 		return vnode.attrs && vnode.attrs.xmlns || nameSpace[vnode.tag]
 	}
 
+	function fail(message) {
+		hookThrown = true
+		hookError = new Error(message)
+	}
+
 	//sanity check to discourage people from doing `vnode.state = ...`
 	function checkState(vnode, original) {
-		if (vnode.state !== original) throw new Error("`vnode.state` must not be modified")
+		if (vnode.state !== original) {
+			fail("`vnode.state` must not be modified")
+		}
 	}
 
 	//Note: the hook is passed as the `this` argument to allow proxying the
@@ -30,6 +38,9 @@ module.exports = function($window) {
 		var original = vnode.state
 		try {
 			return this.apply(original, arguments)
+		} catch (e) {
+			hookThrown = true
+			hookError = e
 		} finally {
 			checkState(vnode, original)
 		}
@@ -155,7 +166,7 @@ module.exports = function($window) {
 		if (vnode.attrs != null) initLifecycle(vnode.attrs, vnode, hooks)
 		initLifecycle(vnode.state, vnode, hooks)
 		vnode.instance = Vnode.normalize(callHook.call(vnode.state.view, vnode))
-		if (vnode.instance === vnode) throw Error("A view cannot return the vnode it received as argument")
+		if (vnode.instance === vnode) fail("A view cannot return the vnode it received as argument")
 		sentinel.$$reentrantLock$$ = null
 	}
 	function createComponent(parent, vnode, hooks, ns, nextSibling) {
@@ -510,7 +521,7 @@ module.exports = function($window) {
 	}
 	function updateComponent(parent, old, vnode, hooks, nextSibling, ns) {
 		vnode.instance = Vnode.normalize(callHook.call(vnode.state.view, vnode))
-		if (vnode.instance === vnode) throw Error("A view cannot return the vnode it received as argument")
+		if (vnode.instance === vnode) fail("A view cannot return the vnode it received as argument")
 		if (vnode.attrs != null) updateLifecycle(vnode.attrs, vnode, hooks)
 		updateLifecycle(vnode.state, vnode, hooks)
 		if (vnode.instance != null) {
@@ -619,7 +630,7 @@ module.exports = function($window) {
 			var content = children[0].children
 			if (vnode.dom.innerHTML !== content) vnode.dom.innerHTML = content
 		}
-		else if (vnode.text != null || children != null && children.length !== 0) throw new Error("Child node of a contenteditable must be trusted")
+		else if (vnode.text != null || children != null && children.length !== 0) fail("Child node of a contenteditable must be trusted")
 	}
 
 	//remove
@@ -852,19 +863,22 @@ module.exports = function($window) {
 		if (typeof source.onupdate === "function") hooks.push(callHook.bind(source.onupdate, vnode))
 	}
 	function shouldNotUpdate(vnode, old) {
+		var prevHookThrown = hookThrown
 		var forceVnodeUpdate, forceComponentUpdate
+		hookThrown = false
 		if (vnode.attrs != null && typeof vnode.attrs.onbeforeupdate === "function") {
 			forceVnodeUpdate = callHook.call(vnode.attrs.onbeforeupdate, vnode, old)
 		}
 		if (typeof vnode.tag !== "string" && typeof vnode.state.onbeforeupdate === "function") {
 			forceComponentUpdate = callHook.call(vnode.state.onbeforeupdate, vnode, old)
 		}
-		if (!(forceVnodeUpdate === undefined && forceComponentUpdate === undefined) && !forceVnodeUpdate && !forceComponentUpdate) {
+		if (hookThrown || !(forceVnodeUpdate === undefined && forceComponentUpdate === undefined) && !forceVnodeUpdate && !forceComponentUpdate) {
 			vnode.dom = old.dom
 			vnode.domSize = old.domSize
 			vnode.instance = old.instance
 			return true
 		}
+		hookThrown = prevHookThrown
 		return false
 	}
 
@@ -878,11 +892,19 @@ module.exports = function($window) {
 		if (dom.vnodes == null) dom.textContent = ""
 
 		vnodes = Vnode.normalizeChildren(Array.isArray(vnodes) ? vnodes : [vnodes])
+		var prevHookError = hookError
+		var prevHookThrown = hookThrown
+		hookThrown = false
 		updateNodes(dom, dom.vnodes, vnodes, hooks, null, namespace === "http://www.w3.org/1999/xhtml" ? undefined : namespace)
 		dom.vnodes = vnodes
 		// document.activeElement can return null in IE https://developer.mozilla.org/en-US/docs/Web/API/Document/activeElement
 		if (active != null && activeElement() !== active && typeof active.focus === "function") active.focus()
 		for (var i = 0; i < hooks.length; i++) hooks[i]()
+		var nextHookThrown = hookThrown
+		var nextHookError = hookError
+		hookThrown = prevHookThrown
+		hookError = prevHookError
+		if (nextHookThrown) throw nextHookError
 	}
 
 	return {render: render, setEventCallback: setEventCallback}