index.test.js

var mongoose = require('mongoose');

var transformProps = require('.');

var SubDocSchema = new mongoose.Schema({
  foo: String
});

var ModelSchema = new mongoose.Schema({
  subDoc: SubDocSchema
});

var Model = mongoose.model('Model', ModelSchema);

describe('transformProps', function() {
  var castToString = function(prop) {
    return String(prop);
  };
  var doc;

  beforeEach(function() {
    doc = new Model({
      subDoc: {foo: 'bar'}
    }).toObject();
  });

  it('throws a TypeError when passed a bad @object', function() {
    var badArgsSet = new Set([
      ['notAnObject', castToString, '_id'],
      [doc, 'notAFunction', '_id'],
      [doc, castToString, function() {
        return 'bad @propKeys';
      }]
    ]);

    badArgsSet.forEach(function(badArgs) {
      // "Note: You must wrap the code in a function, otherwise the error will not be caught and the assertion will fail."
      // https://facebook.github.io/jest/docs/en/expect.html#tothrowerror
      var act = function() {
        transformProps.apply(null, badArgs);
      };

      expect(act).toThrow(TypeError);
    });
  });

  it('can convert `_id`s to string', function() {
    ['_id', ['_id']].forEach(function(propKeysArg) { // Test that @propKeys of type str and single-item array are ok.
      transformProps(doc, castToString, propKeysArg);

      expect(typeof doc._id).toBe('string');
      expect(typeof doc.subDoc._id).toBe('string');
    });
  });

  it('can use multiple transformers', function() {
    var appendHello = function(str) {
      return str + 'Hello!';
    };

    transformProps(doc, [castToString, appendHello], '_id');

    expect(doc._id.substr(-6)).toBe('Hello!');
    expect(doc.subDoc._id.substr(-6)).toBe('Hello!');
  });

  it('can transform multiple props', function() {
    var appendHello = function(str) {
      return str + 'Hello!';
    };

    transformProps(doc, [castToString, appendHello], ['_id', 'foo']);

    expect(doc._id.substr(-6)).toBe('Hello!');
    expect(doc.subDoc._id.substr(-6)).toBe('Hello!');
    expect(doc.subDoc.foo).toBe('barHello!');
  });
});