swagger-api/swagger-editor

export function getPathForPosition({ pos: originalPos, prefix, editorValue, AST }) {
  var pos = Object.assign({}, originalPos)
  var lines = editorValue.split(/\r\n|\r|\n/)
  var previousLine = lines[pos.row - 1] || ""
  var currentLine = lines[pos.row]
  var nextLine = lines[pos.row + 1] || ""
  var prepared = false

  // we're always at the document root when there's no indentation,
  // so let's save some effort
  if (pos.column === 1) {
    return []
  }

  let prevLineIndent = getIndent(previousLine).length
  let currLineIndent = getIndent(currentLine).length

  const isCurrentLineEmpty = currentLine.replace(prefix, "").trim() === ""

  if(
    (previousLine.trim()[0] === "-" || nextLine.trim()[0] === "-")
    && currLineIndent >= prevLineIndent
    && isCurrentLineEmpty
  ) {
    // for arrays with existing items under it, on blank lines
    // example:
    // myArray:
    //   - a: 1
    //   | <-- user cursor
    currentLine += "- a: b" // fake array item
    // pos.column += 1
    prepared = true
  }

  // if current position is in at a free line with whitespace insert a fake
  // key value pair so the generated AST in ASTManager has current position in
  // editing node
  if ( !prepared && isCurrentLineEmpty) {
    currentLine += "a: b" // fake key value pair
    pos.column += 1
    prepared = true
  }

  if(currentLine[currentLine.length - 1] === ":") {
    // Add a space if a user doesn't put one after a colon
    // NOTE: this doesn't respect the "prepared" flag.
    currentLine += " "
    pos.column += 1
  }

    //if prefix is empty then add fake, empty value
  if( !prepared && !prefix){
    // for scalar values with no values
    // i.e. "asdf: "
    currentLine += "~"
  }

  // append inserted character in currentLine for better AST results
  lines[originalPos.row] = currentLine
  editorValue = lines.join("\n")

  let path = AST.pathForPosition(editorValue, {
    line: pos.row,
    column: pos.column
  })

  return path
}

function getIndent(str) {
  let match = str.match(/^ +/)
  return match ? match[0] : ""
}