!Build Status  
``
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`

RawModel.js

> Strongly-typed JavaScript object with support for validation and error handling.

This is a lightweight open source package for the server and browser (using module bundler) written with TypeScript. It's actively maintained, well tested and already used in production environments. The source code is available on GitHub where you can also find our issue tracker.

Related Projects

* vue-rawmodel: RawModel.js plugin for Vue.js v2. Form validation has never been easier!

Introduction

RawModel provides a mechanism for creating strongly-typed data objects with built-in logic for unified data validation and error handling. It has a simple and intuitive API and tends to be a powerful, magic-free, minimalistic and unopinionated framework for writing application data layers where you have a full control. It could be a perfect fit when writing an Express.js action, GraphQL resolver or similar and it's easily extendable.

It provides two core classes:
* Model represents strongly-typed data object with properties.
* Field represents model's property.

Both classes can be used independently but most likely you will use only the Model class.

> We will be using TypeScript for code examples for the rest of the docs. If you haven't picked it up, you should!

Installation

Run the command below to install the package.

`
npm install --save rawmodel
`

This package uses promises thus you need to use Promise polyfill when promises are not supported.

Example

The code below shows a basic usage example.

`js
import { Model } from 'rawmodel';

// defining a basic model
class User extends Model {
public name: string;

public constructor(data = {}) {
super(data);
this.defineField('name');
this.populate(data);
}
}

// usage example
const model = new User({
'name': 'John Smith'
});
model.name; // => 'John Smith'
`

Examples are available inside the ./example folder. You should also check the links below:

* RawModel & ExpressJS: Using RawModel in ExpressJS actions to validate input data and handling data-related errors.

Usage

Below we explain some of the most important features that this package provides. You should check the API section to see a complete list of features.

$3

Model fields are defined using the defineField method. The code below is an example of a basic model class with a name field of type Any.

`js
import { Model } from 'rawmodel';

class User extends Model {
public name: string; // typescript property definition for field name

public constructor(data = {}) {
super(data);
this.defineField('name'); // definition of the name field
}
}

const user = new User();
user.name = 'John Smith';
user.name; // -> "John Smith"
`

$3

Each field has a built-in system for type casting, thus we can force a value to be automatically converted to a specific type when setting a value.

`js
this.defineField('name', {
type: 'String', // automatically cast value to String
});
`

Common types are supported by default. A Model also represents a type. You can define your own types using the defineType method. Please see the API section for a list of all supported types and further details.

$3

As mentioned above, a model also represents a type object. This way you can create complex nested structures by nesting models as shown in the example below.

`js
import { Model } from 'rawmodel';

class Book extends Model {
public title: string;

public constructor(data = {}) {
super(data);
this.defineField('title');
}
}

class User extends Model {
public book: Book;

public constructor(data = {}) {
super(data);
this.defineField('book', {
type: Book,
});
}
}
`

$3

We can set a defaultValue for each field which will automatically populate a field on creation.

The defaultValue can also be a method which returns a dynamic value. This function shares the context of a field instance thus you have access to all the features of the Field class.

`js
this.defineField('name', {
defaultValue () { return this.value },
});
`

$3

Similar to default values, we can set a fakeValue for each field, to populate a field with fake data when calling the fake() method.

The fakeValue can also be a method which returns a dynamic value. This function shares the context of a field instance, thus you have access to all the features of the Field class.

`js
this.defineField('name', {
fakeValue () { return this.value },
});
`

$3

By default, all defined fields are set to null. Similar to default and fake value we can set a nullValue option for each field, to automatically replace null values.

The nullValue can also be a method which returns a dynamic value. Note that this function shares the context of a field instance, thus you have access to all the features of the Field class.

`js
this.defineField('name', {
nullValue () { return '' }, // replace null value
});
`

$3

A field can have a custom getter and a custom setter. These methods all share the context of a field instance, thus you have access to all the features of the Field class.

`js
this.defineField('name', {
get (value) { return value },
set (value) { return value },
});
`

$3

Model's fields are like properties of a Javascript Object. We can easily assign a value to a field through its setter method (e.g. model.name = 'value';). Instead of assigning fields one by one, we can use the populate() method as shown below.

`js
this.populate({
'name': 'John Smith',
'age': 35,
});
`

We can allow only selected fields to be populated by using population strategies (e.g. when populating received form data).

`js
class User extends Model {
public id: string;
public name: string;

public constructor(data = {}) {
super(data);
this.defineField('id', {
populatable: ['internal'], // list population strategy names
});
this.defineField('name', {
populatable: ['input', 'internal'], // list population strategy names
});
}
}

const data = {
'id': 100,
'name': 'John Smith'
};
const user = new User();
user.populate(data); // -> { "id": 100, "name": "John Smith" }
user.populate(data, 'internal'); // -> { "id": 100, "name": "John Smith" }
user.serialize(data, 'input'); // -> { id: null, "name": "John Smith" }
`

$3

Model provides useful methods for object serialization and filtering (check the API for more methods).

`js
const user = new User({
'name': 'John Smith', // initial value
});

user.scroll(function (field) { // argument is an instance of a field
// do something useful
}).then((count) => { // number of processed fields
user.serialize(); // -> { "name": "John Smith" }
});
`

Fields are serializable by default and are thus included in the result object returned by the serialize() method. We can customize the output and include or exclude fields for different occasions by using serialization strategies.

`js
class User extends Model {
public id: string;
public name: string;

public constructor(data = {}) {
super(data);
this.defineField('id', {
serializable: ['output'], // list serialization strategy names
});
this.defineField('name', {
serializable: ['input', 'output'], // list serialization strategy names
});
this.populate(data);
}
}

const user = new User({
'id': 100,
'name': 'John Smith',
});
user.serialize(); // -> { "id": 100, "name": "John Smith" }
user.serialize('input'); // -> { "name": "John Smith" }
user.serialize('output'); // -> { "id": 100, "name": "John Smith" }
`

$3

RawModel tracks changes for all fields and provides a mechanism for committing values and rollbacks.

The example below explains how to setup and use these features.

`js
class User extends Model {
public name: string;

public constructor(data = {}) {
super(data);
this.defineField('name');
}
}

const user = new User();
user.name = 'Mandy Taylor'; // changing field's value
user.isChanged(); // -> true
user.commit(); // set initialValue of each field to the value of value
user.isChanged(); // -> false
user.name = 'Tina Fey'; // changing field's value
user.rollback(); // -> reset value of each field to its initialValue (last committed value)
`

$3

RawModel provides a simple mechanism for validating fields.

`js
class User extends Model {
public name: string;

public constructor(data = {}) {
super(data);

this.defineField('name', {
validate: [ // field validation setup
{ // validator recipe
validator: 'presence', // [required] validator name
message: '%{it} must be present', // [optional] error message
code: 422, // [optional] error code
condition () { return true }, // [optional] condition which switches the validation on/off
it: 'it', // [optional] custom variable for the message
},
],
});
}
}

const user = new User();
user.validate().catch((err) => {
user.collectErrors(); // -> [{path: ['name'], errors: [{validator: 'presence', message: 'is must be present', code: 422}]}]
});
`

It already includes some useful built-in validators but it's super simple to define your own validator. Note that each validator function shares the context of a field instance thus you have access to all the features of the Field class.

`js
class User extends Model {
public name: string;

constructor(data = {}) {
super(data);

this.defineValidator('coolness', function (v) {
return v === 'cool';
});

this.defineField('name', {
validate: [
{
validator: 'coolness',
message: 'must be cool',
},
],
});
}
}
`

$3

RawModel provides a mechanism for handling field-related errors. The logic is aligned with validation thus validation and error handling can easily be managed in a unified way. This is great because we always deal with validation errors and can thus directly send these errors back to a user in a unified format.

`js
class User extends Model {
public name: string;

public constructor(data = {}) {
super(data);

this.defineField('name', {
handle: [ // field error handling setup
{ // handler recipe
handler: 'block', // [required] handler name
message: '%{is} unknown', // [optional] error message
code: 422, // [optional] error code
block (error) { return true }, // [optional] handler-specific function
condition () { return true }, // [optional] condition which switches the handling on/off
is: 'is', // [optional] custom variable for the message
},
],
});
}
}

const error = new Error();
lconstet user = new User();
user.handle(error).then(() => {
user.collectErrors(); // -> [{ path: ['name'], errors: [{ handler: 'block', message: 'is unknown', code: 422 }] }]
});
`

This mechanism is especially handful when saving data to a database. MongoDB could, for example, throw a uniqueness error (E11000) if we try to insert a value that already exists in the database. We can catch that error by using the handle() and then return a unified validation error message to a user.

RawModel already includes some useful built-in handlers but it's super simple to define your own handler. Note that each handler function shares the context of a field instance thus you have access to all the features of the Field class.

`js
class User extends Model {
public name: string;

public constructor(data = {}) {
super(data);

this.defineHandler('coolness', function (e) {
return e.message === 'cool';
});

this.defineField('name', {
handle: [ // field error handling setup
{ // handler recipe
handler: 'coolness', // handler name
message: 'cool', // error message
},
],
});
}
}
`

$3

RawModel.js can be a perfect framework for writing GraphQL resolvers. An instance of a root model, in our case the App class, can represent GraphQL's rootValue.

`js
import { Model } from 'rawmodel';
import { graphql, buildSchema } from 'graphql';

class App extends Model { // root resolver
public hello() { // hello field resolver
return 'Hello World!';
}
}

const schema = buildSchema(
type Query {
hello: String
}
);

const root = new App(); // root resolver

graphql(schema, '{ hello }', root).then((response) => {
console.log(response);
});
`

API

$3

Model({ parent, ...data })

> Abstract class which represents a strongly-typed JavaScript object.

| Option | Type | Required | Default | Description
|--------|------|----------|---------|------------
| parent | Model | Only when used as a submodel | - | Parent model instance.
| data | Object | No | - | Data for populating model fields.

`js
class User extends Model {
public name: string;

public constructor({ parent, ...data } = {}) {
super({ parent }); // initializing the Model

this.defineField('name', {
type: 'String', // [optional] field type casting
populatable: ['input', 'internal'], // [optional] population strategies
serializable: ['input', 'output'], // [optional] serialization strategies
enumerable: true, // [optional] when set to false the field is not enumerable (ignored by Object.keys())
get (v) { return v }, // [optional] custom getter
set (v) { return v }, // [optional] custom setter
validate: [ // [optional] value validator recipes
{ // validator recipe (check validatable.js for more)
validator: 'presence', // [required] validator name
condition () { return true }, // [optional] condition which switches the validation on/off
message: '%{it} must be present', // [optional] error message
code: 422, // [optional] error code
it: 'it' // [optional] custom variable for the message
}
],
handle: [ // [optional] error handling recipies
{ // handler recipe
handler: 'block', // [optional] handler name
condition () { return true }, // [optional] condition which switches the handling on/off
message: '%{is} unknown', // [optional] error message
code: 422, // [optional] error code
block (error) { return true }, // [optional] handler-specific function
is: 'is' // [optional] custom variable for the message
}
],
defaultValue: 'Noname', // [optional] field default value (value or function)
fakeValue: 'Noname', // [optional] field fake value (value or function)
});

this.populate(data); // [optional] a good practice to enable data population from model constructor
this.commit(); // [optional] a good practice to commit default data
}
}
`

Model.prototype.applyErrors(errors): Model

> Deeply populates fields with the provided errors.

`js
model.applyErrors([
{
path: ['books', 1, 'title'], // field path
errors: [
{
validator: 'presence', // or handler: ''
message: 'is required',
code: 422,
},
],
},
]);
`

Model.prototype.clear(): Model

> Sets all model fields to null.

Model.prototype.clone(): Model

> Returns a new Model instance which is the exact copy of the original.

Model.prototype.collect(handler): Array

> Scrolls through model fields and collects results.

| Option | Type | Required | Default | Description
|--------|------|----------|---------|------------
| handler | Function | Yes | - | A handler method which is executed for each field.

Model.prototype.collectErrors(): Array

> Returns a list of errors for all the fields ({path, errors}[]).

`js
model.collectErrors(); // => { path: ['name'], errors: [{ validator: 'absence', message: 'must be blank', code: 422 }] }
`

Model.prototype.commit(): Model

> Sets initial value of each model field to the current value of a field. This is how field change tracking is restarted.

Model.prototype.defineField(name, { type, populatable, serializable, enumerable, get, set, defaultValue, fakeValue, validate }): Void

> Defines a new model property.

| Option | Type | Required | Default | Description
|--------|------|----------|---------|------------
| name | String | Yes | - | Property name.
| populatable | String[] | No | undefined | Population strategies (used by .populate()).
| serializable | String[] | No | undefined | Serialization strategies (used by .serialize()).
| enumerable | Boolean | No | true | When set to false the field is not enumerable (ignored by Object.keys()).
| type | String, Model | No | - | Data type (pass a Model to create a nested structure; check typeable.js for more).
| get | Function | No | - | Custom getter.
| set | Function | No | - | Custom setter.
| defaultValue | Any | No | - | Field default value.
| fakeValue | Any | No | - | Field fake value.
| validate | Array | No | - | List of validation recipies (check validatable.js for more).

Model.prototype.defineType(name, converter): Void

> Defines a custom data type.

| Option | Type | Required | Default | Description
|--------|------|----------|---------|------------
| name | String | Yes | - | Type name.
| converter | Function | Yes | - | Type converter.

Model.prototype.defineValidator(name, handler): Void

> Defines a custom validator.

| Option | Type | Required | Default | Description
|--------|------|----------|---------|------------
| name | String | Yes | - | Validator name.
| handler | Function, Promise | Yes | - | Validator handler.

Model.prototype.equals(value): Boolean

> Returns true when the provided value represents an object with the same fields as the model itself.

Model.prototype.failFast(fail): Void

> Configures validator to stop field validation on the first error.

| Option | Type | Required | Default | Description
|--------|------|----------|---------|------------
| fail | Boolean | No | false | Stops field validation on the first error when set to true.

Model.prototype.fake(): Model

> Sets each model field to its fake value if the fake value generator is defined.

Model.prototype.filter(handler): Object

> Converts a model into serialized data object with only the keys that pass the test.

| Option | Type | Required | Default | Description
|--------|------|----------|---------|------------
| handler | Function | Yes | - | A function to test each key value. If the function returns true then the key is included in the returned object.

Model.prototype.flatten(): Array

> Converts the model into an array of fields.

`js
user.flatten(); // -> [{path: [...], field: ...}, ...]
`

Model.prototype.getField(...keys): Field

> Returns a class instance of a field at path.

| Option | Type | Required | Default | Description
|--------|------|----------|---------|------------
| keys | Array | Yes | - | Path to a field (e.g. ['book', 0, 'title']).

Model.prototype.handle(error, { quiet }): Promise(Model)

> Tries to handle the error against each field handlers and populates the model with possible errors.

| Option | Type | Required | Default | Description
|--------|------|----------|---------|------------
| error | Any | Yes | - | Error to be handled.
| quiet | Boolean | No | true | When set to false, a handled validation error is thrown. This doesn't affect the unhandled errors (they are always thrown).

`js
try {
// throws an error (e.g. you can call the validate() method)
}
catch (e) {
model.handle(e);
}
`

Model.prototype.hasErrors(): Boolean

> Returns true when no errors exist (inverse of isValid()). Make sure that you call the validate() method first.

Model.prototype.hasField(...keys): Boolean

> Returns true when a field path exists.

| Option | Type | Required | Default | Description
|--------|------|----------|---------|------------
| keys | Array | Yes | - | Path to a field (e.g. ['book', 0, 'title']).

Model.prototype.isChanged(): Boolean

> Returns true if at least one model field has been changed.

Model.prototype.isNested(): Boolean

> Returns true if nested fields exist.

Model.prototype.isValid(): Boolean

> Returns true when all model fields are valid (inverse of hasErrors()). Make sure that you call the validate() method first.

Model.prototype.invalidate(): Model

> Clears errors on all fields.

Model.prototype.options: Object

> Model options.

Model.prototype.parent: Model

> Parent model instance.

Model.prototype.populate(data, strategy): Model

> Applies data to a model.

| Option | Type | Required | Default | Description
|--------|------|----------|---------|------------
| data | Object | Yes | - | Data object.
| strategy | String | No | - | When the strategy name is provided, only the fields where the populatable option includes this strategy name are populated. If the parameter is not provided then all fields are included in the process.

Model.prototype.reset(): Model

> Sets each model field to its default value.

Model.prototype.rollback(): Model

> Sets each model field to its initial value (last committed value). This is how you can discharge model changes.

Model.prototype.root: Model

> The first model instance in a tree of models.

Model.prototype.scroll(handler): Integer

> Scrolls through model fields and executes a handler on each field.

| Option | Type | Required | Default | Description
|--------|------|----------|---------|------------
| handler | Function | Yes | - | A handler method which is executed for each field.

Model.prototype.serialize(strategy): Object

> Converts a model into serialized data object.

| Option | Type | Required | Default | Description
|--------|------|----------|---------|------------
| strategy | String | No | - | When the strategy name is provided, the output will include only the fields where the serializable option includes this strategy name. If the parameter is not provided then all fields are included in the result.

Model.prototype.validate({ quiet }): Promise(Model)

> Validates model fields, populates the model with possible errors and throws a validation error if not all fields are valid unless the quiet is set to true.

| Option | Type | Required | Default | Description
|--------|------|----------|---------|------------
| quiet | Boolean | No | true | When set to false, a validation error is thrown.

`js
try {
await model.validate(); // throws a validation error when invalid fields exist
}
catch (e) {
// e is a 422 validation error
}
`

$3

Field({ type, get, set, defaultValue, fakeValue, validate, validators, handle, handlers, owner, failFast })

> A model field.

| Option | Type | Required | Default | Description
|--------|------|----------|---------|------------
| type | String, Model | No | - | Data type (pass a Model to create a nested structure).
| get | Function | No | - | Custom getter.
| set | Function | No | - | Custom setter.
| defaultValue | Any | No | - | Field default value.
| fakeValue | Any | No | - | Field fake value.
| validate | Array | No | - | List of validator recipes.
| handle | Array | No | - | List of error handler recipes.
| validators | Object | No | - | Custom validators.
| handlers | Object | No | - | Custom handlers.
| owner | Model | No | - | An instance of a Model which owns the field.
| failFast | Boolean | No | false | Stops validation on the first error when set to true.

Field.prototype.cast(value): Any

> Returns transformed value based on field's type.

Field.prototype.clear(): Field

> Sets field and related subfields to null.

Field.prototype.commit(): Field

> Sets initial value to the current value. This is how field change tracking is restarted.

Field.prototype.defaultValue: Any

> A getter which returns the default field value.

Field.prototype.errors: Object[]

> List of field errors (sets the validate method).

Field.prototype.equals(value): Boolean

> Returns true when the provided value represents an object that looks the same.

| Option | Type | Required | Default | Description
|--------|------|----------|---------|------------
| value | Any | Yes | - | A value to compare to.

Field.prototype.fake(): Field

> Sets field to a generated fake value.

Field.prototype.fakeValue: Any

> A getter which returns a fake field value.

Field.prototype.handle(error): Promise(Field)

> Validates the value and populates the errors property with errors.

| Option | Type | Required | Default | Description
|--------|------|----------|---------|------------
| error | Any | Yes | - | Error to be handled.

Field.prototype.hasErrors(): Boolean

> Returns true when no errors exist (inverse of isValid()). Make sure that you call the validate() method first.

Field.prototype.initialValue: Any

> A getter which returns the last committed field value.

Field.prototype.isChanged(): Boolean

> Returns true if the field or at least one subfield have been changed.

Field.prototype.isNested(): Boolean

> Returns true if the field is a nested model.

Field.prototype.isValid(): Boolean

> Returns true if the field and all subfields are valid (inverse of hasErrors()). Make sure that you call the validate() method first.

Field.prototype.invalidate(): Field

> Clears the errors field on all fields (the reverse of validate()).

Field.prototype.options: Object

> A getter which returns field options.

Field.prototype.owner: Model

> A getter which returns a reference to a Model instance on which the field is defined.

Field.prototype.recipe: Object

> A getter which returns a field recipe object.

Field.prototype.reset(): Field

> Sets the field to its default value.

Field.prototype.rollback(): Field

> Sets the field to its initial value (last committed value). This is how you can discharge field's changes.

Field.prototype.type: Any

> A getter which returns field type (set to Model for a nested structure).

Field.prototype.validate(): Promise(Field)

> Validates the value and populates the errors property with errors.

Field.prototype.value: Any

> Field current value (the actual model's property).

$3

| Type | Description
|------|------------
| 'Any' | A value of different types (excluding arrays).
| ['Any'] | An array with values of different types.
| 'String' | A string value.
| ['String'] | An array of string values.
| 'Boolean' | A boolean value.
| ['Boolean'] | An array of boolean values.
| 'Number' | An integer or a float number.
| ['Number'] | An array of integer or float numbers.
| 'Integer' | An integer number.
| ['Integer'] | An array of integer numbers.
| 'Float' | A float number.
| ['Float'] | An array of float numbers.
| 'Date' | A date.
| ['Date'] | An array of dates.

NOTE: Field data type should always represent a value. This means that you should never assign a function to a field. If you need to handle dynamic field values, please use field value transformations instead. You can also define your own data type by using the defineType method.

$3

absence

> Validates that the specified field is blank.

arrayExclusion

> Validates that the specified field is not in an array of values.

| Option | Type | Required | Default | Description
|--------|------|----------|---------|------------
| values | Array | Yes | - | Array of restricted values.

arrayInclusion

> Validates that the specified field is in an array of values.

| Option | Type | Required | Default | Description
|--------|------|----------|---------|------------
| values | Array | Yes | - | Array of allowed values.

arrayLength

> Validates the size of an array.

| Option | Type | Required | Default | Description
|--------|------|----------|---------|------------
| min | Number | No | - | Allowed minimum items count.
| minOrEqual | Number | No | - | Allowed minimum items count (allowing equal).
| max | Number | No | - | Allowed maximum items count.
| maxOrEqual | Number | No | - | Allowed maximum items count (allowing equal).

block

> Validates the specified field against the provided block function. If the function returns true then the field is treated as valid.

| Option | Type | Required | Default | Description
|--------|------|----------|---------|------------
| block | Function,Promise | Yes | - | Synchronous or asynchronous function (e.g. async () => true)

`js
const recipe = {
validator: 'block',
message: 'must be present',
async block (value, recipe) { return true },
};
`

numberSize

> Validates the size of a number.

| Option | Type | Required | Default | Description
|--------|------|----------|---------|------------
| min | Number | No | - | Allowed minimum value.
| minOrEqual | Number | No | - | Allowed minimum value (allowing equal).
| max | Number | No | - | Allowed maximum value.
| maxOrEqual | Number | No | - | Allowed maximum value (allowing equal).

presence

> Validates that the specified field is not blank.

stringBase64

> Validates that the specified field is base64 encoded string.

stringDate

> Validates that the specified field is a date string.

| Option | Type | Required | Default | Description
|--------|------|----------|----------|-----------
| iso | Boolean | No | false | When true only ISO-8601 date format is accepted.

stringEmail

> Validates that the specified field is an email.

| Option | Type | Required | Default | Description
|--------|------|----------|---------|------------
| allowDisplayName | Boolean | No | false | When set to true, the validator will also match name