Global error management

index.js

@@ -4,6 +4,7 @@ var hyperscript = require("./hyperscript")
 var request = require("./request")
 var mountRedraw = require("./mount-redraw")
 var domFor = require("./render/domFor")
+var errorManager = require("./util/errorManager")
 
 var m = function m() { return hyperscript.apply(this, arguments) }
 m.m = hyperscript
@@ -22,5 +23,6 @@ m.buildPathname = require("./pathname/build")
 m.vnode = require("./render/vnode")
 m.censor = require("./util/censor")
 m.domFor = domFor.domFor
+m.errorManager = errorManager.em
 
 module.exports = m

render/render.js

@@ -2,6 +2,8 @@
 
 var Vnode = require("../render/vnode")
 var df = require("../render/domFor")
+var errorManager = require("../util/errorManager").em
+
 var delayedRemoval = df.delayedRemoval
 var domFor = df.domFor
 
@@ -151,8 +153,12 @@ module.exports = function($window) {
 		}
 		initLifecycle(vnode.state, vnode, hooks)
 		if (vnode.attrs != null) initLifecycle(vnode.attrs, 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")
+		try {
+			vnode.instance = Vnode.normalize(callHook.call(vnode.state.view, vnode))
+		} catch (e) {
+			vnode.instance = Vnode.normalize(errorManager.fail(e, vnode, true))
+		}
+		if (vnode.instance === vnode) errorManager.fail("A view cannot return the vnode it received as argument", vnode, false)
 		sentinel.$$reentrantLock$$ = null
 	}
 	function createComponent(parent, vnode, hooks, ns, nextSibling) {
@@ -460,8 +466,12 @@ module.exports = function($window) {
 		}
 	}
 	function updateComponent(parent, old, vnode, hooks, nextSibling, ns) {
-		vnode.instance = Vnode.normalize(callHook.call(vnode.state.view, vnode))
-		if (vnode.instance === vnode) throw Error("A view cannot return the vnode it received as argument")
+		try {
+			vnode.instance = Vnode.normalize(callHook.call(vnode.state.view, vnode))
+		} catch (e) {
+			vnode.instance = Vnode.normalize(errorManager.fail(e, vnode, true))
+		}
+		if (vnode.instance === vnode) errorManager.fail("A view cannot return the vnode it received as argument", vnode, false)
 		updateLifecycle(vnode.state, vnode, hooks)
 		if (vnode.attrs != null) updateLifecycle(vnode.attrs, vnode, hooks)
 		if (vnode.instance != null) {
@@ -700,7 +710,7 @@ module.exports = function($window) {
 				if (vnode.tag === "option" && old !== null && vnode.dom.value === "" + value) return
 				//setting input[type=file][value] to different value is an error if it's non-empty
 				// Not ideal, but it at least works around the most common source of uncaught exceptions for now.
-				if (isFileInput && "" + value !== "") { console.error("`value` is read-only on file inputs!"); return }
+				if (isFileInput && "" + value !== "") { errorManager.log(0, "`value` is read-only on file inputs!"); return }
 				/* eslint-enable no-implicit-coercion */
 			}
 			vnode.dom[key] = value
@@ -748,7 +758,7 @@ module.exports = function($window) {
 	}
 	function updateAttrs(vnode, old, attrs, ns) {
 		if (old && old === attrs) {
-			console.warn("Don't reuse attrs object, use new object for every redraw, this will throw in next major")
+			errorManager.log(1, "Don't reuse attrs object, use new object for every redraw, this will throw in next major")
 		}
 		if (attrs != null) {
 			// If you assign an input type that is not supported by IE 11 with an assignment expression, an error will occur.

util/errorManager.js

@@ -0,0 +1,83 @@
+"use strict"
+
+// Log levels are:
+// * 0 error
+// * 1 warning
+// * 2 info
+// * 3 debug
+
+module.exports = {
+  em: {
+    logEventListeners:[],
+    failEventListeners:[],
+
+    log(level, message) {
+      this.executeListeners(
+        this.logEventListeners, 
+        {level:level,message:message},
+        () => {
+          switch (level) {
+            case 0:
+              console.error(message)
+              break;
+            case 1:
+              console.warn(message)
+              break;
+            case 2:
+              console.info(message)
+              break;
+            case 3:
+              console.debug(message)
+              break;
+          }
+        })
+    },
+
+    fail(error, vnode, inView) {
+      return this.executeListeners(
+        this.failEventListeners,
+        {error:error, vnode:vnode, inView:inView},
+        () => {
+          this.debugVnode(0, vnode)
+          if (error instanceof Error) 
+            throw error
+          else
+            throw new Error(error)
+        }
+      )
+    },
+
+    debugVnode(level, vnode) {
+      if (vnode) {
+        this.log(level, "Component: " + vnode.tag.name + " with attributes " + JSON.stringify(vnode.attrs))
+      }
+    },
+
+    addEventListener(name, callback) {
+      switch (name) {
+        case "log":
+          this.addToArray(this.logEventListeners, callback)
+          break
+        case "fail":
+          this.addToArray(this.failEventListeners, callback)
+          break
+      }
+    },
+
+    executeListeners(listeners, param, defaultHandler) {
+      let stopProcessing = false;
+      for (let i=0 ; i<listeners.length ; i++) {
+        let returnValue = listeners[i](param, () => {stopProcessing=true})
+        if (stopProcessing) return returnValue
+      }
+      defaultHandler()
+    },
+
+    addToArray(array, object) {
+      for (let i=0 ; i<array.length ; i++) {
+        if (array[i] === object) return
+      }
+      array.push(object)
+    }
+  }
+}