Brace closer

closer.js

module.exports = closer;

function closer(codeString) {
  var lines = codeString.split('\n');
  var lastIndent = 0;
  var currentScope = { indent: 0, children: [] };
  for (lineIndex = 0; lineIndex < lines.length; lineIndex++) {
    var line = lines[lineIndex];
    var currentIndent = /^\s*/.exec(line)[0].length;
    if (/^\s*√\s*$/.test(line)) {
      var scope = currentScope;
      var out = [];
      while (scope && scope.indent > currentIndent) {
        out = out.concat(scope.openers.split('').reverse().map(c => ({
          '{': '}',
          '(': ')',
          '[': ']'
        })[c]));

        scope = scope.parent;
      }
      lines[lineIndex] = ' '.repeat(currentIndent) + out.join('')
    } else {
      if (currentIndent > lastIndent) {
        currentScope = { parent: currentScope, indent: currentIndent, children: [] }
        currentScope.parent.children.push(currentScope);
        currentScope.openers = /[[{(]*$/.exec(lines[lineIndex - 1])[0];
      } else {
        currentScope = currentScope.parent
      }
    }
  }
  console.log(lines.join('\n'))
}

result.js

  const someNumber = 123;
  doSomething(
    function() {
      somethingElse([
        function() {
          bar({
            x: function() {
              return 22;
  }})}])})

  const ok = 'ok';

test.js

var closer = require('./');

var testString = function() {/*
  const someNumber = 123;
  doSomething(
    function() {
      somethingElse([
        function() {
          bar({
            x: function() {
              return 22;
  √

  const ok = 'ok';
*/}.toString().split('\n').slice(1, -1).join('\n');

closer(testString)