ezobjects

EZ Objects v3.0.0

EZ Objects is a Node.js module (that can also be usefully browserify'd) that aims to save you lots of time writing class objects that are strictly typed in JavaScript. All you have to do is create simple configurations for each of your objects and then create them using the createClass() function.

• Installation
• Examples
• EZ Object Method Signatures
• Module Exports
• Configuration Specifications
• Contributing
• License

Installation

npm install --save ezobjects

Examples

const ezobjects = require(`ezobjects`);

/** Configure a basic EZ Object example */
const configBasicExample = {
  className: 'BasicExample',
  properties: [
    { name: 'name', type: 'string' }
  ]
};

/** Create the `BasicExample` class */
ezobjects.createClass(configBasicExample);

/** Create a new instance of the `BasicExample` class */
const basicExample1 = new BasicExample();

/** Give it a name using the auto-generated setter */
basicExample1.name('Basic Example 1');

/** Output the instance to console */
console.log(basicExample1);

/** 
 * Create another instance of the `BasicExample` class, but this time
 * initialize it with a plain object passed to the constructor.
 */
const basicExample2 = new BasicExample({
  name: 'Basic Example 2'
});

/** 
 * Configure a full EZ Object example demonstrating all supported types,
 * including the ability to extend other objects.
 */
const configFullExample = {
  className: 'FullExample',
  extends: BasicExample,
  properties: [
    { name: 'exampleInt', type: 'int' },
    { name: 'exampleFloat', type: 'float' },
    { name: 'exampleString', type: 'string' },
    { name: 'exampleBoolean', type: 'boolean' },
    { name: 'exampleFunction', type: 'function' },
    { name: 'exampleDate', type: 'date' },
    { name: 'exampleBuffer', type: 'buffer' },
    { name: 'exampleOtherObj', type: 'BasicExample' },
    
    { name: 'exampleIntArray', type: 'array', arrayOf: { type: 'int' } },
    { name: 'exampleFloatArray', type: 'array', arrayOf: { type: 'float' } },
    { name: 'exampleStringArray', type: 'array', arrayOf: { type: 'string' } },
    { name: 'exampleBooleanArray', type: 'array', arrayOf: { type: 'boolean' } },
    { name: 'exampleFunctionArray', type: 'array', arrayOf: { type: 'function' } },
    { name: 'exampleDateArray', type: 'array', arrayOf: { type: 'date' } },
    { name: 'exampleBufferArray', type: 'array', arrayOf: { type: 'buffer' } },
    { name: 'exampleOtherObjArray', type: 'array', arrayOf: { type: 'BasicExample' } } 
  ]
};

/** Create the `FullExample` class */
ezobjects.createClass(configFullExample);

/** Create a new instance of the `FullExample` class */
const fullExample = new FullExample({
  name: `Full Example`,
  exampleInt: 293,
  exampleFloat: 194.13489,
  exampleString: `What's up, doc?`,
  exampleBoolean: true,
  exampleFunction: arg => `Hello, ${arg}!`,
  exampleDate: new Date('1776-07-04'),
  exampleBuffer: Buffer.from([0x04, 0x7F, 0x93, 0x38]),
  exampleOtherObj: basicExample1,
  
  exampleIntArray: [293, -178, 492],
  exampleFloatArray: [194.13489, -2890.25, -0.04281],
  exampleStringArray: [`What's up, doc?`, `Shiver me timbers`],
  exampleBooleanArray: [true, false, true],
  exampleFunctionArray: [arg => `Hello, ${arg}!`, arg => `Farewell, ${arg}!`],
  exampleDateArray: [new Date('1776-07-04'), new Date('1945-12-07')],
  exampleBufferArray: [Buffer.from([0x04, 0x7F, 0x93, 0x38]), Buffer.from('A string instead')],
  exampleOtherObjArray: [basicExample1, basicExample2]
});

/** Output the instance to console */
console.log(fullExample);

/** Output one of the function responses to console */
console.log(fullExample.exampleFunctionArray()[1]('Rich'));

/** Try to set a `float` property with a `string` */
try {
  /**
   * This throws a TypeError since string given, not float; the same behavior 
   * can be expected for all other types, including arrays of types.
   */
  fullExample.exampleFloat('test');
} catch ( err ) {
  /** Output error message to console */
  console.log(err.message);
}

Expected Output

BasicExample { _name: 'Basic Example 1' }
FullExample {
  _name: 'Full Example',
  _exampleInt: 293,
  _exampleFloat: 194.13489,
  _exampleString: 'What\'s up, doc?',
  _exampleBoolean: true,
  _exampleFunction: [Function: exampleFunction],
  _exampleDate: 1776-07-04T00:00:00.000Z,
  _exampleBuffer: <Buffer 04 7f 93 38>,
  _exampleOtherObj: BasicExample { _name: 'Basic Example 1' },
  _exampleIntArray: [ 293, -178, 492 ],
  _exampleFloatArray: [ 194.13489, -2890.25, -0.04281 ],
  _exampleStringArray: [ 'What\'s up, doc?', 'Shiver me timbers' ],
  _exampleBooleanArray: [ true, false, true ],
  _exampleFunctionArray: [ [Function], [Function] ],
  _exampleDateArray: [ 1776-07-04T00:00:00.000Z, 1945-12-07T00:00:00.000Z ],
  _exampleBufferArray: 
   [ <Buffer 04 7f 93 38>,
     <Buffer 41 20 73 74 72 69 6e 67 20 69 6e 73 74 65 61 64> ],
  _exampleOtherObjArray: 
   [ BasicExample { _name: 'Basic Example 1' },
     BasicExample { _name: 'Basic Example 2' } ] }
Farewell, Rich!
FullExample.exampleFloat(string): Invalid signature, requires 'float'.

EZ Object Method Signatures

These are the object method signatures that all of your EZ Objects will have, though note that you can always add other functionality by adding to the object prototype:

new MyObject([data])

• Parameter: data - PlainObject - (optional)
• Description: Create a new MyObject object and initialize it using either defaults or any provided key/value pairs in the plain object data. Keys can either be equal to the name of a property, or they can be have an underscore before the name of a property, as would be the case if you were to JSON.stringify() and then JSON.parse() an EZ Object. This allows for easy transferability in cases where JSON is used as the transfer medium.

new MyObject([data])

• Parameter: data - string - (optional)
• Description: Create a new MyObject object and initialize it using either defaults or any provided key/value pairs in the JSON encoded string data. Keys can either be equal to the name of a property, or they can be have an underscore before the name of a property, as would be the case if you were to JSON.stringify() an EZ Object. This allows for easy transferability in cases where JSON is used as the transfer medium.

MyObject.init([data])

• Parameter: data - PlainObject
• Description: Initialize this object using either defaults or any provided key/value pairs in the plain object data. This is also the method used by the constructor.

In addition, each property you define will have a single method that is a getter and setter, and it will have the following signatures:

MyObject.myProperty()

• Returns: mixed
• Description: Get the value of the property.

MyObject.myProperty(value)

• Parameter: value - mixed
• Throws: TypeError if value is not of the correct javascript data type for myProperty
• Returns: this
• Description: Set the value of the property, throwing a TypeError if the javascript data type does not match the configuration, this is how the strict typing is implemented. This signature returns this to allow for set call chaining.

Module Exports

The EZ Objects module exports two functions:

ezobjects.createClass(objectConfig)

• Description: A function that creates an ES6 class corresponding to the configuration outlined in objectConfig, with constructor, initializer, getters, setters.

ezobjects.instanceOf(obj, constructorName)

• Description: A helper function for testing whether obj is an descendant of a constructor constructorName.

Configuration Specifications

See the following for how to configure your EZ Objects:

An object configuration can have the following:

• className - string - (required) Name of the class
• properties - Array - (required) An array of property configurations that the object should have corresponding properties for
• extends - mixed - (optional) The object that the new object should be extended from [required to extend object]

A property configuration can have the following:

• name - string - (required) Name of the property, must conform to JavaScript rules
• type - string - (optional) JavaScript data type, or types if separated by the pipe | character, that the property must be equal to -- types can be int, float, string, boolean, date, buffer, function, any other valid object constructor name, or Array where arrayOf is provided with information about the array element types. [either type and/or instanceOf is required]
• instanceOf - string - (optional) JavaScript class constructor name, or names if separated by the pipe | character, that the property must be an instance of [either type and/or instanceOf is required]
• default - mixed - (optional) Sets the default value for the property in the class object
• arrayOf - string - (required for type array) A plain object containing he EZ Object type or instanceOf of the elements of the array -- types can be int, float, string, boolean, date, buffer, function, any other valid object constructor name
• initTransform(x) - function - (optional) Function that transforms and returns the property value prior to initializing (does not affect ezobjects defaults or custom defaults)
• getTransform(x) - function - (optional) Function that transforms and returns the property value prior to getting
• setTransform(x) - function - (optional) Function that transforms and returns the property value prior to setting

Default intiailizations for different EZ Object types

• int - 0
• double - 0
• string - ``
• boolean - false
• function - function () { }
• Date - new Date(0)
• Buffer - Buffer.from([])
• Array - []
• Everything else - null

Contributing

Please open an issue on the GitHub repository if you find any broken functionality or other bugs/errors. Feature requests will also be accepted, but are not guaranteed to be implemented.

License

MIT Licensed