@newtral/class-transformer

Install

``bash
npm install @newtral/class-transformer class-transformer
`

Usage

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Provide a default value when the value is not present or it is undefined

`typescript
import { Default } from '@newtral/class-transformer';
import { plainToClass } from 'class-transformer';

class Client {
@Default('http://localhost:3000') // Or using a function @Default(() => 'http://localhost:3000')
baseUrl: string;
}

const client = plainToClass(Client, {});
console.log(client.baseUrl); // 'http://localhost:3000'

const client = plainToClass(Client, { baseUrl: 'https://example.com' });
console.log(client.baseUrl); // 'https://example.com'
`

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Transform the property into an array. When the value is undefined there is not action. When the
value is not an array it gets transformer into an array of one element. This could be useful when
obtaining multiple query string values but the user only selects one item.

`typescript
import { ToArray } from '@newtral/class-transformer';
import { plainToClass } from 'class-transformer';

class User {
@ToArray()
postIds: string[];
}

const client = plainToClass(User, { postIds: '12345' });
console.log(client.postIds); // ['2345']
`

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A default value can be provided due how to
this bug in class-transformer. It uses
the yn package for transformations

`typescript
import { ToBoolean } from '@newtral/class-transformer';
import { plainToClass } from 'class-transformer';

class User {
@ToBoolean({ default: false })
isAdmin: boolean;
}

const user = plainToClass(User, { isAdmin: 'true' });
console.log(user.isAdmin); // true
`

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Transform an object id value to string an vice versa using the following conventions:

- It will do nothing if the value is undefined
- plain to class or class to class: If the object is a string it uses new ObjectId(value)
- class to plain: converts the object id to it string representation

`typescript
import { ToObjectId } from '@newtral/class-transformer';
import { ObjectId } from 'bson';
import { classToPlain, plainToClass } from 'class-transformer';

class User {
@ToObjectId()
_id: ObjectId;
}

const user = plainToClass(User, { _id: '5ed116e81723fcd8ed3d230b' });
console.log(user._id instanceof ObjectId); // true

const plainUser = classToPlain(user);
console.log(typeof user._id); // 'string'
console.log(user._id); // '5ed116e81723fcd8ed3d230b'
`

Development

The project use husky and
lint-staged for linting and fixing possible errors on
source code before commit

Git hooks scripts are installed after running npm install the first time

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Compile typescript files from the src folder inside the lib folder

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Compile typescript files from the src folder inside the esm folder using es modules

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Concurrently run both build:commonjs and build:esm

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Remove the following directories/files

- lib
- esm
- reports

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Run tests files inside the tests folder that matches the following patterns. Exit with code > 0 on
error

- \*.test.ts
- \*.spec.ts

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The same as npm test and generates coverages reports in reports/coverage. Exit with code > 0 on
error

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Check eslint errors according to .eslintrc

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Run npm run lint` applying fixes and run prettier on every typescript file

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Check for:

- Build errors
- Tests failures
- Lint errors

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Run test and generate every possible report. Do not exit with error code > 0 if the tests fail. It
generates a report file instead

- reports/lint-checkstyle.xml Lint report in chackstyle format
- reports/test-results.xml Test report in xUnit format
- reports/coverage/clover.xml Coverage report in clover format
- reports/coverage/cobertura-coverage.xml Coverage report in cobertura format
- reports/coverage/lcov.info Coverage report in lcov
- reports/coverage/index.html Coverage report in html