Get function parameter names for interface purposes

Question

can anyone help me on how to retrieve function parameter names? For example:

var A = function(a, b, c) {};

I need to get the parameter name

Answer 1

You can use either a regex such as described in here, another alternative would be to use a tokenizer. The following code uses the acorn javascript parser for checking if a function contains a specific argument name:

function isFunction(value) {
  return value && typeof value === 'function';
}

function hasArgument(func, name) {

if (!isFunction(func) || !name) {
    return false;
}

var tokenizer = acorn.tokenize(func);
var token = tokenizer();

while (token.type.type !== 'eof') {

    // ')' closes function, we do not want to look inside the function body
    if (token.type.type === ')') {
        return false;
    }

    if (token.type.type === 'name' && token.value === name) {
        return true;
    }

    token = tokenizer();

}

return false;

}