The ast.js code for DEFNODE looks as follows: DEFNODE(‘name’, ‘desc’, ‘parameters’) where name is the name of the node, desc is the description of the node, and parameters is the list of parameters of the node. By using the above code example, we can see that the name variable is the critical aspect of the node in function DEFNODE. So, the first thing to do in case of an issue with this variable is to check whether the variable is defined or not in ast.js. To do that, you can use the following code. var undefined = typeof(undefined) == ‘undefined’;
Solution: Check whether the variable is defined or not in ast.js
If the variable is defined, then you can proceed with your code. If it's not defined, you can use the following code to define it: var name = '';
Why is DEFNODE checked for undefined?
The critical aspect of the node in function DEFNODE is the name variable. In cases when the name variable is not defined, it will cause an error. So, to avoid any errors and make sure that no code breakages occur, the name variable must be defined by using the following code line: var name = ‘name’;
Finding a Variable in an Object
You should also check whether the name variable is defined in the outer function.
var undefined = typeof(undefined) == ‘undefined’; if (undefined){ alert("The name variable is not defined!"); }
Check for undefined variable in JavaScript
The first step in debugging any issue is to check whether the variable in question is defined or not. If it's not defined, then we know that it could be an error with the code. To do this, you can use the following JavaScript code. var undefined = typeof(undefined) == ‘undefined’;
If undefined is not defined, then it means that there was an error with the code. This makes sense because if there's no expression for a variable, then there should be no value assigned to that variable as well. So, now you know where the problem lies and you can continue debugging your JavaScript code.
Check if AST variable is defined or not in JavaScript
The above code checks if the variable undefined is defined or not. The result of the code is false, which means that the variable is not defined in the JavaScript and it can be used as a node key. If so, check whether the value assigned to this variable is correct. That is, if you are trying to create a new node with name ‘name’, then check whether you have assigned a valid value to this variable.