Parse YAML preserving comments in a given JSON property

parseWithComments.js

const yaml = require('yaml');
const recurse = require('reftools/lib/recurse.js').recurse;

const ast = yaml.parseDocument(inputStr);

recurse(ast,{},function(obj,key,state){
  let comment;
  if (obj[key] && obj[key].commentBefore) {
    comment = obj[key].commentBefore;
  }
  if (obj[key] && obj[key].comment) {
    comment = obj[key].comment;
  }
  if (comment && Array.isArray(state.parent)) {
    let existing = state.parent.find(function(e,i,a){
      if (e.key.value === '$comment') return true;
    });
    if (existing) {
      existing.value.value += '\n' + comment;
    }
    else {
      state.parent.push(ast.createPair('$comment',comment));
    }
  }
});

return ast.toJSON();