Json stable stringify - amd ready

json-stable-stringify.js

define(function () {

  'use strict';

  return function (obj, opts) {
    if (!opts) {
      opts = {};
    }

    if (typeof opts === 'function') {
      opts = { cmp: opts };
    }

    var space = opts.space || '';

    if (typeof space === 'number') {
      space = new Array(space+1).join(' ');
    }

    var cycles = (typeof opts.cycles === 'boolean') ? opts.cycles : false;
    var replacer = opts.replacer || function(key, value) { return value; };

    var cmp = opts.cmp && (function (f) {
      return function (node) {
        return function (a, b) {
          var aobj = { key: a, value: node[a] };
          var bobj = { key: b, value: node[b] };
          return f(aobj, bobj);
        };
      };
    })(opts.cmp);

    var seen = [];
    return (function stringify (parent, key, node, level) {
      /*jshint maxcomplexity: 12 */
      var indent = space ? ('\n' + new Array(level + 1).join(space)) : '';
      var colonSeparator = space ? ': ' : ':';
      var out = [];

      if (node && node.toJSON && typeof node.toJSON === 'function') {
        node = node.toJSON();
      }

      node = replacer.call(parent, key, node);

      if (node === undefined) {
        return;
      }

      if (typeof node !== 'object' || node === null) {
        return JSON.stringify(node);
      }

      if (Array.isArray(node)) {

        node.forEach(function (curNode, index) {
          var item = stringify(node, index, curNode, level + 1) || JSON.stringify(null);
          out.push(indent + space + item);
        });

        return '[' + out.join(',') + indent + ']';

      } else {

        if (seen.indexOf(node) !== -1) {

          if (cycles) {
            return JSON.stringify('__cycle__');
          }
          throw new TypeError('Converting circular structure to JSON');

        } else {
          seen.push(node);
        }

        Object
          .keys(node)
          .sort(cmp && cmp(node))
          .forEach(function (key) {
            var value = stringify(node, key, node[key], level+1);

            if (value) {
              var keyValue = JSON.stringify(key) + colonSeparator + value;
              out.push(indent + space + keyValue);
            }
          });

        return '{' + out.join(',') + indent + '}';
      }
    })({ '': obj }, '', obj, 0);
  };
});