How to find a JavaScript variable's transitive usage through function calls?

Question

Suppose I have access to the full set of source that could potentially be using a JavaScript variable foo .

Some of the source code looks like this:

foo.bar = 'baz';

(function(a, b, c) {
    a();
    b.bar = 'whee';
    c();
}(fn, foo, fn));

Are there any tools available (ESLint rules, NPM modules, etc.) that could identify all usages of the foo variable here? I'm after a list of all access of the variable, including within scopes and including nested objects. So, it would have to identify:

• The foo.bar usage in the global scope
• The foo usage in the function invocation
• The b.bar call is an access of foo.bar

Answer 1

http://ternjs.net/doc/manual.html#infer seems like a good lead:

infer.findRefs(ast: AST, scope: Scope, name: string, refScope: Scope, f: fn(AST, Scope))
Will traverse the given syntax tree, using scope as the starting scope, looking for references to variable name that resolve to scope refScope, and call f with the node of the reference and its local scope for each of them.

infer.findPropRefs(ast: AST, scope: Scope, objType: Obj, propName: string, f: fn(AST))
Analogous to findRefs, but used to look for references to a specific property instead. Whereas findRefs is precise, this is dependent on type inference, and thus can not be relied on to be precise.