astwalker improved

libs/remix-debug/src/source/astWalker.js

@@ -21,13 +21,15 @@ AstWalker.prototype.walk = function (ast, callback) {
   if (!('*' in callback)) {
     callback['*'] = function () { return true }
   }
-  const nodes = ast.nodes || (ast.body && ast.body.statements) || ast.declarations
-  if(ast.body && ast.initializationExpression) // 'for' loop handling
-    nodes.push(ast.initializationExpression)
-  if (manageCallBack(ast, callback) && nodes && nodes.length > 0) {
-    for (let k in nodes) {
-      const child = nodes[k]
-      this.walk(child, callback)
+  if(ast){
+    const nodes = ast.nodes || (ast.body && ast.body.statements) || ast.declarations || []
+    if(ast.body && ast.initializationExpression) // 'for' loop handling
+      nodes.push(ast.initializationExpression)
+    if (manageCallBack(ast, callback) && nodes && nodes.length > 0) {
+      for (let k in nodes) {
+        const child = nodes[k]
+        this.walk(child, callback)
+      }
     }
   }
 }