How to differentiate between variables and functions

[tannakartikey]

I want to extract all the variables from a formula.

I am traversing through the Expression Tree using the traverse method to get all the SymbolNodes.

The problem is that the functions like sqrt, pi, sin are considered as SymbolNode.

Is there any way I can ignore all those values? Right now I am doing the following to differentiate them:

typeof math[node.name] === 'function' ? 'This is function' : 'This is symbol'

The pi is not a function either.

I want to do this so that I can ask the user for those values and then set the scope using the user input to evaluate the formula.

Is there any better way to handle this?

[josdejong]

Good question. An expression with a function like sin(2) is parsed into a FunctionNode with a property .fn containing a SymbolNode with name sin. To check whether a SymbolNode is the name of a function, you can check whether it's parent is a FunctionNode or not.

[zagushka]

@tannakartikey
I'm working on the same task, in addition to @josdejong comment
sin(x) parsed to two SymbolNodes - sin and x with the same FunctionNode parent. So additional check parent have the same name is required.
My final check node is variable node.isSymbolNode && parent?.name !== node.name;