Check for error before proccessing graph

src/App.js

@@ -37,21 +37,24 @@ class App extends React.Component {
                         endRow: 0,
                         endCol: 0,
                         className: "",
-                        type: ""}],
+                        type: ""
+                    }],
                     js: [{
                         startRow: 0,
                         startCol: 0,
                         endRow: 0,
                         endCol: 0,
                         className: "",
-                        type: ""}],
+                        type: ""
+                    }],
                     arm: [{
                         startRow: 0,
                         startCol: 0,
                         endRow: 0,
                         endCol: 0,
                         className: "",
-                        type: ""}]
+                        type: ""
+                    }]
                 },
                 children: [{}]
             }
@@ -84,7 +87,9 @@ class App extends React.Component {
 
     readInputCallBack = (codeToEval) => {
         eval(codeToEval);
-        window.EMULATOR_CONSOLE_READ = () => { return window.prompt()};
+        window.EMULATOR_CONSOLE_READ = () => {
+            return window.prompt()
+        };
     };
 
     clearConsole = () => {
@@ -110,31 +115,37 @@ class App extends React.Component {
 
     };
     proccesLine = () => {
-        if(this.state.statementIndex < this.state.mainStatements.length){
+        if (this.state.statementIndex < this.state.mainStatements.length) {
             let current = this.state.currentNode;
             let jsLines = this.state.js.code.split(/;\n(?!})/);
             // console.log(jsLines)
             // console.log(current)
             let codeLine = jsLines[current.highlighting.js[0].startRow];
             codeLine = codeLine.replace("var ", "window.");
-            eval(codeLine);;
+            eval(codeLine);
+            ;
             let newIndex = this.state.statementIndex + 1;
             this.setState({
                 currentNode: this.state.mainStatements[newIndex],
-                statementIndex: newIndex})
+                statementIndex: newIndex
+            })
         } else {
             console.log("Finished executing code")
         }
     };
 
     getStatements = () => {
+        if (typeof this.state.graphData.children !== "undefined") {
             let rootChildren = this.state.graphData.children;
             let funcMain = rootChildren[rootChildren.length - 1];
             let mainFuncStatementsNode = funcMain.children[0];
             let mainFuncStatements = mainFuncStatementsNode.children;
-       this.setState({mainStatements: mainFuncStatements,
+            this.setState({
+                mainStatements: mainFuncStatements,
                 currentNode: mainFuncStatements[0],
-           statementIndex: 0})
+                statementIndex: 0
+            })
+        }
     };
 
     render() {
@@ -148,16 +159,21 @@ class App extends React.Component {
                                     <ButtonStrip
                                         onCompileClick={(e) => {
                                             this.processWaccCode(this.state.wacc.code).then(() => {
+                                                    if (typeof this.state.graphData.children !== "undefined") {
                                                         this.clearConsole()
-                                            this.getStatements()})
+                                                        this.getStatements()
+                                                    }
+                                                }
+                                            )
                                         }}
                                         onExecuteClick={(e) => {
                                             eval(this.state.js.code)
                                             eval("waccPrintFinished()")
                                         }}
                                         onStepWaccClick={(e) => {
-                                            this.readInputCallBack(e)
+                                            this.proccesLine()
                                         }}
+
                                             />
                                             </CardBody>
                                             </Card>
@@ -235,6 +251,6 @@ class App extends React.Component {
                                             </div>
                                             )
                                             }
-}
+                                            }
 
-export default App;
+                                            export default App;