Hydrator Next

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Next gen Class hydration library, super slim ~1Kb. Written mostly for Typescript. Works in both node and browser. While it is possible to use with plain JS it will require some pre-processor like babel with decorators support.

Only depends on reflect-metadata polyfil.

For Typescript, you need to have these two options turned on in tsconfig.json:

{
	"compilerOptions": {
		"emitDecoratorMetadata": true,
		"experimentalDecorators": true
	}
}

WARNING: API is not yet final

Requirements

Technically it should have no requirements.

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Docs

Read the docs here

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Installation

For yarn:

yarn add hydrator-next

For npm:

npm i hydrator-next

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For browser just include the script or import it via ES6 import statement.

Some examples

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Imports:

// ES6 JS/Typescript style
import { Hydrator } from 'hydrator-next';

// require

const { Hydrator } = require('hydrator-next');

Basic usage:

class Test {
	some = 1;
	property = 'a';
}

// hydrate from raw data
const obj = Hydrator.hydrate(Test, {some: 2, property: 'b'});

FieldType options (all of them are optional):

Property	Type	Description
type	string	Property type, has to be registered with Converter.registerConverter
nested	constructor	If property is another nested class, explicitly state the class, ex. Date
array	boolean	Is property an array, need to also provide type otherwise it will have no effect
converter	(value: any, direction: DataDirection, type: string) => any;	custom converter function, example of usage below
translate	string	Should this property be translated into some other field when hydrating/dehydrating, useful for mapping plain object under_score_case to camelCaseProperty
translateDatabase	string	Same as translate however will only have effect when hydrating/dehydrating to database
ignoreDatabase	boolean	value will be ignored when coming or going to database, which basically means field does not exist in database
ignorePlain	boolean	value will be ignored when coming or going to plain object, which basically means field should not be hydrated while operating on raw data
ignore	boolean	value will be ignored, won't ever be touched by Hydrator

Advanced usage:

Converter.registerConverter('string', convertString);
Converter.registerConverter('number', convertNumber);
Converter.registerConverter('bigint', convertBigInt);

function customConverter(value: any, direction: DataDirection, type: string) {
	switch (direction) {
		case DataDirection.FromDatabase:
		case DataDirection.FromPlain:
			return '_' + value;
		case DataDirection.ToDatabase:
		case DataDirection.ToPlain:
			return value.substr(1);
	}
}

class TestClassCustom {
	@FieldType({ converter: customConverter })
	cust: any;
	
	// Forced to string upon hydration
	@FieldType({ type: 'string' })
	str: string;
	
	// Forced to number upon hydration
	@FieldType({ type: 'number' })
	num: string;

	// Forced to BigInt upon hydration
	@FieldType({ type: 'bigint' })
	bi: string;
	
	// Any data will come here
	fieldOfAnyValue: any = null;

	// Will not be changed at all upon migration
	@FieldType({ ignore: true })
	ignorethis: string = '9';
}

Hydrator.hydrate(TestClassCustom, {
	cust: 'a',
	str: 123,
	num: '999',
	bi: 123123,
	fieldOfAnyValue: new Date(),
	// field is not decorated nor present as property in class, thus will be ignored.
	willBeIgnored: 'aaa',
	ignorethis: 'nope'
})