traverse - find all global references

[kumavis]

Is there a better way to do this? or perhaps an existing package?
@babel/traverse's scopes seem to track all reference to bound values but not to globals

'use strict';

const { default: traverse } = require('@babel/traverse')

const nonReferenceIdentifiers = [
  'FunctionDeclaration',
  'FunctionExpression',
  'ClassMethod',
  'LabeledStatement',
  'BreakStatement',
  'ContinueStatement',
  'CatchClause',
  'ArrayPatten',
  'RestElement'
]

module.exports = { findGlobals }

function findGlobals (ast) {
  const globals = new Map()
  traverse(ast, {
    // ReferencedIdentifier
    Identifier: (path) => {
      // skip if not being used as reference
      const parentType = path.parent.type
      if (nonReferenceIdentifiers.includes(parentType)) return
      if (parentType === 'VariableDeclarator' && path.parent.id === path.node) return
      // skip if this is the key side of a member expression
      if (parentType === 'MemberExpression' && path.parent.property === path.node) return
      // skip if this is the key side of an object pattern
      if (parentType === 'ObjectProperty' && path.parent.key === path.node) return
      
      // skip if it refers to an existing variable
      const name = path.node.name
      if (path.scope.hasBinding(name, true)) return
      
      // check if arguments refers to a var, this shouldn't happen in strict mode
      if (name === 'arguments') {
        if (isInFunctionDeclaration(path)) return
      }

      // save global
      saveGlobal(path)
    },
    ThisExpression: (path) => {
      if (isInFunctionDeclaration(path)) return
      saveGlobal(path, 'this')
    }
  })

  return globals

  function saveGlobal (path, name = path.node.name) {
    // init entry if needed
    if (!globals.has(name)) {
      globals.set(name, [])
    }
    // append ref
    const refsForName = globals.get(name)
    refsForName.push(path)
  }
}

function isInFunctionDeclaration (path) {
  return getParents(path.parentPath).some(parent => parent.type === 'FunctionDeclaration')
}

function getParents (nodePath) {
  const parents = []
  let target = nodePath
  while (target) {
    parents.push(target.node)
    target = target.parentPath
  }
  parents.reverse()
  return parents
}

[nicolo-ribaudo]

We have a ReferencedIdentifier "virtual" type: maybe this would help?

function findGlobals (ast) {
  const globals = new Map()
  traverse(ast, {
    // ReferencedIdentifier
    ReferencedIdentifier: (path) => {
      // skip if it refers to an existing variable
      const name = path.node.name
      if (path.scope.hasBinding(name, true)) return
      
      // check if arguments refers to a var, this shouldn't happen in strict mode
      if (name === 'arguments') {
        if (isInFunctionDeclaration(path)) return
      }

      // save global
      saveGlobal(path)
    },
    ThisExpression: (path) => {
      if (isInFunctionDeclaration(path)) return
      saveGlobal(path, 'this')
    }
  })

[kumavis]

thanks! that simplifies things a bit. i would expect this functionality to be provided by the context object