json2yaml.js/index.js

(function () {
  "use strict";

  var typeOf = require('remedial').typeOf
    ;

  function stringify(data) {
    var handlers
      , indentLevel = ''
      ;

    handlers = {
        "undefined": function () {
          // objects will not have `undefined` converted to `null`
          // as this may have unintended consequences
          // For arrays, however, this behavior seems appropriate
          return 'null';
        }
      , "null": function () {
          return 'null';
        }
      , "number": function (x) {
          return x;
        }
      , "boolean": function (x) {
          return x ? 'true' : 'false';
        }
      , "string": function (x) {
          // to avoid the string "true" being confused with the
          // the literal `true`, we always wrap strings in quotes
          return JSON.stringify(x);
        }
      , "array": function (x) {
          var output = ''
            ;

          if (0 === x.length) {
            output += '[]';
            return output;
          }

          indentLevel = indentLevel.replace(/$/, '  ');
          x.forEach(function (y) {
            // TODO how should `undefined` be handled?
            var handler = handlers[typeOf(y)]
              ;

            if (!handler) {
              throw new Error('what the crap: ' + typeOf(y));
            }

            output += '\n' + indentLevel + '- ' + handler(y);
             
          });
          indentLevel = indentLevel.replace(/  /, '');
          
          return output;
        }
      , "object": function (x) {
          var output = ''
            ;

          if (0 === Object.keys(x).length) {
            output += '{}';
            return output;
          }

          indentLevel = indentLevel.replace(/$/, '  ');
          Object.keys(x).forEach(function (k) {
            var val = x[k]
              , handler = handlers[typeOf(val)]
              ;

            if ('undefined' === typeof val) {
              // the user should do
              // delete obj.key
              // and not
              // obj.key = undefined
              // but we'll error on the side of caution
              return;
            }

            if (!handler) {
              throw new Error('what the crap: ' + typeOf(val));
            }

            output += '\n' + indentLevel + k + ': ' + handler(val);
          });
          indentLevel = indentLevel.replace(/  /, '');

          return output;
        }
      , "function": function () {
          // TODO this should throw or otherwise be ignored
          return '[object Function]';
        }
    };

    return '---' + handlers[typeOf(data)](data) + '\n';
  }

  module.exports.stringify = stringify;
}());