is-reference-identifier.ts

import type { Identifier } from 'ts-morph'

const referenceCache = new WeakMap<Identifier, boolean>()

/** Determines if an identifier is a reference. */
export function isReferenceIdentifier(node: Identifier) {
  const cached = referenceCache.get(node)

  if (cached !== undefined) {
    return cached
  }

  const parentNode = node.getParent()
  let isReference = true

  for (const definitionNode of node.getDefinitionNodes()) {
    if (definitionNode === parentNode) {
      isReference = false
      break
    }
  }

  referenceCache.set(node, isReference)

  return isReference
}