Properties becomes undefined and then not

Bug Report

• I would like to work on a fix!

Current behavior

Using path.node.declarations[0].init.arguments[0].properties where path.node is a VariableDeclaration always causes an error claiming that is undefined but when I use console.log to print it, it prints it’s value (not undefined), and then creates an error saying that it is undefined when it isn’t. Some of my code uses ES6 filter in two instances. When I create a third instance, having my code print path.node.declarations[0].init.arguments[0].properties == undefined has it print true and then false and then creates an error that it is undefined when using filter on it.

Expected behavior A clear and concise description of what you expected to happen (or code).

Babel Configuration (babel.config.js, .babelrc, package.json#babel, cli command, .eslintrc)

• Filename: babel.config.js

{
  "your": { "config": "here" }
}

Environment

• Babel version(s): [v6.26.3]
• Node/npm version: [Node 12.16.1/6.14.17]
• OS: [Windows 10 10.0.18363]
• Monorepo: [no]

Additional context This appears when I am writing a plugin using the visitor pattern.

[shadowtime2000]

@shadowtime2000 Can you share a reproduction repo?

@JLHwung shadowtime2000/react-class-functional on branch experimental

[shadowtime2000]

@JLHwung

import React from "react";

const Hey = React.createClass({
  componentDidMount() {
    console.log("a");
    console.log("b");
  },

  componentWillUnmount() {
    console.log("Hey component unmounted");
  },

  render() {
    return <div>Hey!</div>;
  }
});

export default Hey;