import com.google.javascript.jscomp.NodeTraversal.AbstractShallowCallback; //导入依赖的package包/类
/**
 * Returns the set of references to storage locations (both variables
 * and the heap) under {@code root}.
 */
private Set<Node> findStorageLocationReferences(Node root) {
  final Set<Node> references = Sets.newHashSet();
 
  NodeTraversal.traverse(compiler, root, new AbstractShallowCallback() {
    @Override
    public void visit(NodeTraversal t, Node n, Node parent) {
      if (NodeUtil.isGet(n)
          || (NodeUtil.isName(n) && !NodeUtil.isFunction(parent))) {
        references.add(n);
      } 
    }       
  });
  
  return references;
}
 

import com.google.javascript.jscomp.NodeTraversal.AbstractShallowCallback; //导入依赖的package包/类
/**
 * Returns the set of references to storage locations (both variables
 * and the heap) under {@code root}.
 */
private Set<Node> findStorageLocationReferences(Node root) {
  final Set<Node> references = Sets.newHashSet();

  NodeTraversal.traverse(compiler, root, new AbstractShallowCallback() {
    @Override
    public void visit(NodeTraversal t, Node n, Node parent) {
      if (NodeUtil.isGet(n)
          || (n.isName() && !parent.isFunction())) {
        references.add(n);
      }
    }
  });

  return references;
}
 

import com.google.javascript.jscomp.NodeTraversal.AbstractShallowCallback; //导入依赖的package包/类
/**
 * Returns the set of references to storage locations (both variables
 * and the heap) under {@code root}.
 */
private Set<Node> findStorageLocationReferences(Node root) {
  final Set<Node> references = new HashSet<>();

  NodeTraversal.traverseEs6(compiler, root, new AbstractShallowCallback() {
    @Override
    public void visit(NodeTraversal t, Node n, Node parent) {
      if (NodeUtil.isGet(n)
          || (n.isName() && !parent.isFunction())) {
        references.add(n);
      }
    }
  });

  return references;
}
 

import com.google.javascript.jscomp.NodeTraversal.AbstractShallowCallback; //导入依赖的package包/类
private void checkDefaultParam(
    Var param, final Scope scope, final Set<String> varsInFunctionBody) {
  NodeTraversal.traverseEs6(
      compiler,
      param.getParentNode().getSecondChild(),
      /**
       * Do a shallow check since cases like:
       *   function f(y = () => x, x = 5) { return y(); }
       * is legal. We are going to miss cases like:
       *   function f(y = (() => x)(), x = 5) { return y(); }
       * but this should be rare.
       */
      new AbstractShallowCallback() {
        @Override
        public void visit(NodeTraversal t, Node n, Node parent) {
          if (!NodeUtil.isReferenceName(n)) {
            return;
          }
          String refName = n.getString();
          if (varsInFunctionBody.contains(refName) && !scope.isDeclared(refName, true)) {
            compiler.report(JSError.make(n, EARLY_REFERENCE_ERROR, refName));
          }
        }
      });
}