Documentation/Example for folding specific nodes

v6
#1

I’m trying to understand how I can create a foldEffect when I already know which SyntaxNodes I want to fold.

I found that I can iterate the tree:

  const view = editor;
  const from = 0;
  const to = editor.state.doc.length;
  
  let effects = [];
  syntaxTree(view.state).iterate({
      from, to,
      enter: (node) => {
        console.log(node.name, node);
        
        if(node.name == "Object") {
          const range = foldable(view.state, node.from, node.to)
          effects.push(foldEffect.of(range));
        }
      }
    })
  
  if (effects.length) view.dispatch({effects: effects})

but am unclear on what the effect needs to be (the above doesn’t work - it throws an exception and doesn’t fold anything).

image

Thanks!

#2

I don’t think foldable means what you think it means. You pass it the start/end of a line and it will see if the registered fold services provide a foldable range for that line. If you know which range you want to fold, you should not be calling foldable, and definitely not with the extent of a syntax node, which probably does not precisely cover a line.

#3

Thanks. Would you mind pointing me in the right direction?

My usecase is:

  • I have a JSON file that I’m displaying
  • I want to fold nodes initially to make it easier for users to navigate
  • simple example:
{
  "a": {
    "prop":"someValue"
  },
  "b": {
    "otherProp": 5
  },
  "c": 5
}

I’d like to fold all objects - that is, “a” and “b” in this example - after loading this text. “a” and “b” could have arbitrary depth and also arbitrary other child objects.

A folow-up question would be if I can pass additional metadata into SyntaxNodes to map them back to javascript objects - a goal would be that when a user clicks on a button related to “a”, I can focus the right line where “a” starts.

#4

The approach would roughly be to use syntaxTree (or ensureSyntaxTree) to get the parse tree, iterate over it with its iterate method, and collect foldEffects to dispatch.

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