[FR] minimal folding options

[andykais]

I would love to see the ability to fold a single level like methods on classes, or top-level functions only.
It looks like suggestions like this have been rejected before (#888). However, I wonder if options like these would be less agressive to fold. The use case is working with very large react files that have a single class with many methods on them. A small example would be this:

import * as React from "react";

class App extends React.Component {
  state = {
    isShowing: true
  };

  handleOnClick = () => {
    // fold this function
  };

  render() {
    // fold this function
    const { props, state } = this;

    return (
      <div>
        <button onClick={this.handleOnClick}>
          {state.isShowing ? "hide" : "show"}
        </button>

        {state.isShowing && (
          <div>
            {props.list.map(image => (
              <img src={image.src} alt="" />
            ))}
          </div>
        )}
      </div>
    );
  }
}

export default App;

are the main constraints on not adding fine grained control to folding the cpu load?

[zdm]

Guys, could you, please, review my PR #1136 .
It solves problem completely and makes folds fully configurable.
If PR is acceptable I can update it to match the latest code.