Workaround Dredd hook for nullable type attributes in API Blueprint

hooks.js

var hooks = require('hooks');

// Recursively add null as acceptable type if there is string
// "#nullable" present in the property description
var patchPropertiesWithNullable = function(schema) {
  if (typeof(schema['properties']) == 'object' && ! Array.isArray(schema['properties'])){
    for (property in schema['properties']){
      var partialSchemaToPatch = schema['properties'][property];
      schema['properties'][property] = patchPropertiesWithNullable(partialSchemaToPatch);
    };
  };

  if (schema['description'] !== undefined) {
    if (schema['description'].indexOf("#nullable") > -1) {
      if (schema['type'] === undefined) {
        schema['type'] = 'null';

      } else if (typeof(schema['type']) == 'string') {
        schema['type'] = [schema['type'], 'null'];

      } else if (Array.isArray(schema['type'])) {
        schema['type'].push('null');

      };
    };
  };

  return(schema);
};

hooks.beforeAll(function(transactions, callback) {
  for(index in transactions) {
    var transaction = transactions[index];
    if(transaction['expected']['bodySchema'] !== undefined){
      var schema = JSON.parse(transaction['expected']['bodySchema']);
      schema = patchPropertiesWithNullable(schema);
      transactions[index]['expected']['bodySchema'] = JSON.stringify(schema, null, 2);
    };
  };

  callback();
});