diff --git a/src/App.js b/src/App.js
index 3c2b4b95f683ac49c4e13dcf36dc79e55949ca47..42b53e261c27f2860648e6c4b60348e3da75ab79 100644
--- a/src/App.js
+++ b/src/App.js
@@ -31,27 +31,30 @@ class App extends React.Component {
                 name: "",
                 attributes: {value: ""},
                 highlighting: {
-                    wacc:   [{
+                    wacc: [{
                         startRow: 0,
                         startCol: 0,
                         endRow: 0,
                         endCol: 0,
                         className: "",
-                        type: ""}],
-                    js:     [{
+                        type: ""
+                    }],
+                    js: [{
                         startRow: 0,
                         startCol: 0,
                         endRow: 0,
                         endCol: 0,
                         className: "",
-                        type: ""}],
-                    arm:    [{
+                        type: ""
+                    }],
+                    arm: [{
                         startRow: 0,
                         startCol: 0,
                         endRow: 0,
                         endCol: 0,
                         className: "",
-                        type: ""}]
+                        type: ""
+                    }]
                 },
                 children: [{}]
             }
@@ -68,15 +71,15 @@ class App extends React.Component {
     }
 
     onNodeOver = (nodeData, evt) => {
-      let hl = nodeData.highlighting;
+        let hl = nodeData.highlighting;
 
-      this.setState((state, props) => {
-          state.wacc.markers = hl.wacc;
-          state.js.markers = hl.js;
-          state.arm.markers = hl.arm;
+        this.setState((state, props) => {
+            state.wacc.markers = hl.wacc;
+            state.js.markers = hl.js;
+            state.arm.markers = hl.arm;
 
-          return state
-      })
+            return state
+        })
     }
 
     onNodeOut = (nodeData, evt) => {
@@ -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 = () => {
-       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,
-           currentNode: mainFuncStatements[0],
-           statementIndex: 0})
+        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,
+                currentNode: mainFuncStatements[0],
+                statementIndex: 0
+            })
+        }
     };
 
     render() {
@@ -148,93 +159,98 @@ class App extends React.Component {
                                     <ButtonStrip
                                         onCompileClick={(e) => {
                                             this.processWaccCode(this.state.wacc.code).then(() => {
-                                            this.clearConsole()
-                                            this.getStatements()})
+                                                    if (typeof this.state.graphData.children !== "undefined") {
+                                                        this.clearConsole()
+                                                        this.getStatements()
+                                                    }
+                                                }
+                                            )
                                         }}
                                         onExecuteClick={(e) => {
                                             eval(this.state.js.code)
                                             eval("waccPrintFinished()")
                                         }}
                                         onStepWaccClick={(e) => {
-                                            this.readInputCallBack(e)
+                                            this.proccesLine()
                                         }}
-                                    />
-                                </CardBody>
-                            </Card>
-                        </GridItem>
-                        <GridItem xs={12} sm={12} md={4}>
-                            <Card>
-                                <CardBody>
-                                    <CodeEditor
-                                        heading='WACC Code'
-                                        onCodeChange={this.onWaccCodeChange}
-                                        value={this.state.wacc.code}
-                                        markers={this.state.wacc.markers}/>
-                                </CardBody>
-                            </Card>
-                        </GridItem>
-                        <GridItem xs={12} sm={12} md={4}>
 
-                            <Card>
-                                <CardBody>
-                                    <CodeEditor
-                                        heading='JavaScript'
-                                        value={this.state.js.code}
-                                        markers={this.state.js.markers}
-                                        readOnly={true}/>
-                                </CardBody>
-                            </Card>
-                        </GridItem>
-                        <GridItem xs={12} sm={12} md={4}>
-                            <Card>
-                                <CardBody>
-                                    <CodeEditor
-                                        heading='ARM Assembly'
-                                        value={this.state.arm.code}
-                                        markers={this.state.arm.markers}
-                                        readOnly={true}/>
-                                </CardBody>
-                            </Card>
-                        </GridItem>
-                        <GridItem xs={12} sm={12} md={8}>
-                            <Card>
-                                <CardBody>
-                                    <div style={{height: '50em'}}>
-                                        <Tree
+                                            />
+                                            </CardBody>
+                                            </Card>
+                                            </GridItem>
+                                            <GridItem xs={12} sm={12} md={4}>
+                                            <Card>
+                                            <CardBody>
+                                            <CodeEditor
+                                            heading='WACC Code'
+                                            onCodeChange={this.onWaccCodeChange}
+                                            value={this.state.wacc.code}
+                                            markers={this.state.wacc.markers}/>
+                                            </CardBody>
+                                            </Card>
+                                            </GridItem>
+                                            <GridItem xs={12} sm={12} md={4}>
+
+                                            <Card>
+                                            <CardBody>
+                                            <CodeEditor
+                                            heading='JavaScript'
+                                            value={this.state.js.code}
+                                            markers={this.state.js.markers}
+                                            readOnly={true}/>
+                                            </CardBody>
+                                            </Card>
+                                            </GridItem>
+                                            <GridItem xs={12} sm={12} md={4}>
+                                            <Card>
+                                            <CardBody>
+                                            <CodeEditor
+                                            heading='ARM Assembly'
+                                            value={this.state.arm.code}
+                                            markers={this.state.arm.markers}
+                                            readOnly={true}/>
+                                            </CardBody>
+                                            </Card>
+                                            </GridItem>
+                                            <GridItem xs={12} sm={12} md={8}>
+                                            <Card>
+                                            <CardBody>
+                                            <div style={{height: '50em'}}>
+                                            <Tree
                                             collapsible={false}
                                             data={this.state.graphData}
                                             onMouseOver={this.onNodeOver}
                                             onMouseOut={this.onNodeOut}
                                             orientation="vertical"/>
-                                    </div>
-                                </CardBody>
-                            </Card>
-                        </GridItem>
-                        <GridItem xs={12} sm={12} md={4}>
-                            <Card>
-                                <CardBody>
-                                    <div
-                                        style={{
+                                            </div>
+                                            </CardBody>
+                                            </Card>
+                                            </GridItem>
+                                            <GridItem xs={12} sm={12} md={4}>
+                                            <Card>
+                                            <CardBody>
+                                            <div
+                                            style={{
                                             display: "flex",
                                             justifyContent: "center",
                                             alignItems: "center",
                                             height: "50em"
-                                        }}
-                                    >
-                                        <Terminal commandPassThrough={cmd => {
+                                            }}
+                                            >
+                                            <Terminal commandPassThrough={cmd => {
                                             window.EMULATOR_CONSOLE_READ = () => {return cmd[0]};
                                             window.EMULATOR_IS_INPUT = true;
-                                        }} watchConsoleLogging hideTopBar allowTabs={false} key={this.state.consoleReset}/>
-                                    </div>
-                                </CardBody>
-                            </Card>
-                        </GridItem>
-
-                    </GridContainer>
-                </div>
-            </div>
-        )
-    }
-}
+                                            }} watchConsoleLogging hideTopBar allowTabs={false} key={this.state.consoleReset}/>
+                                            </div>
+                                            </CardBody>
+                                            </Card>
+                                            </GridItem>
+
+                                            </GridContainer>
+                                            </div>
+                                            </div>
+                                            )
+                                            }
+                                            }
 
-export default App;
+                                            export default App;