@codemirror/legacy-modes/mode/asciiarmor.js

Collection of ported legacy language modes for the CodeMirror code editor

function errorIfNotEmpty(stream) {
  var nonWS = stream.match(/^\s*\S/);
  stream.skipToEnd();
  return nonWS ? "error" : null;
}

export const asciiArmor = {
  name: "asciiarmor",
  token: function(stream, state) {
    var m;
    if (state.state == "top") {
      if (stream.sol() && (m = stream.match(/^-----BEGIN (.*)?-----\s*$/))) {
        state.state = "headers";
        state.type = m[1];
        return "tag";
      }
      return errorIfNotEmpty(stream);
    } else if (state.state == "headers") {
      if (stream.sol() && stream.match(/^\w+:/)) {
        state.state = "header";
        return "atom";
      } else {
        var result = errorIfNotEmpty(stream);
        if (result) state.state = "body";
        return result;
      }
    } else if (state.state == "header") {
      stream.skipToEnd();
      state.state = "headers";
      return "string";
    } else if (state.state == "body") {
      if (stream.sol() && (m = stream.match(/^-----END (.*)?-----\s*$/))) {
        if (m[1] != state.type) return "error";
        state.state = "end";
        return "tag";
      } else {
        if (stream.eatWhile(/[A-Za-z0-9+\/=]/)) {
          return null;
        } else {
          stream.next();
          return "error";
        }
      }
    } else if (state.state == "end") {
      return errorIfNotEmpty(stream);
    }
  },
  blankLine: function(state) {
    if (state.state == "headers") state.state = "body";
  },
  startState: function() {
    return {state: "top", type: null};
  }
};