https://github.com/tim-maes/facet

Source generator that instantly scaffolds DTOs, typed LINQ projections, and ViewModels without any runtime overhead.
https://github.com/tim-maes/facet

facet generator mapper mapping model object source

Last synced: 7 months ago
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Source generator that instantly scaffolds DTOs, typed LINQ projections, and ViewModels without any runtime overhead.

• Host: GitHub
• URL: https://github.com/tim-maes/facet
• Owner: Tim-Maes
• License: mit
• Created: 2025-04-22T19:31:43.000Z (8 months ago)
• Default Branch: master
• Last Pushed: 2025-06-03T20:56:55.000Z (7 months ago)
• Last Synced: 2025-06-04T00:33:15.985Z (7 months ago)
• Topics: facet, generator, mapper, mapping, model, object, source
• Language: C#
• Homepage:
• Size: 110 KB
• Stars: 65
• Watchers: 3
• Forks: 2
• Open Issues: 3
• Metadata Files:
  • Readme: README.md
  • License: LICENSE.txt

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README

          
# Facet

> "One part of a subject, situation, object that has many parts."

[![NuGet](https://img.shields.io/nuget/v/Facet.svg)](https://www.nuget.org/packages/Facet)

[![Downloads](https://img.shields.io/nuget/dt/Facet.svg)](https://www.nuget.org/packages/Facet)

![License: MIT](https://img.shields.io/badge/license-MIT-blue.svg)

**Facet** is a C# source generator that lets you define **lightweight projections** (DTOs, API models, etc.) directly from your domain models — without writing boilerplate.

It generates partial classes, records, structs, or record structs with constructors, optional LINQ projections, and even supports custom mappings — all at compile time, with zero runtime cost.

---

## What is Facetting?

Facetting is the process of defining **focused views** of a larger model at compile time.

Instead of manually writing separate DTOs, mappers, and projections, **Facet** allows you to declare what you want to keep — and generates everything else.

You can think of it like **carving out a specific facet** of a gem:

- The part you care about

- Leaving the rest behind.

## Why Facetting?

- Reduce duplication across DTOs, projections, and ViewModels

- Maintain strong typing with no runtime cost

- Stay DRY (Don't Repeat Yourself) without sacrificing performance

- Works seamlessly with LINQ providers like Entity Framework

## Key Features

- :white_check_mark: Generate classes, records, structs, or record structs from existing types

- :white_check_mark: Exclude fields/properties you don't want (create a Facetted view of your model)

- :white_check_mark: Include/redact public fields

- :white_check_mark: Auto-generate constructors for fast mapping

- :white_check_mark: LINQ projection expressions `(Expression>)`

- :white_check_mark: Custom mapping via `IFacetMapConfiguration`

## Documentation

- **[Documentation & Guides](docs/README.md)**

- [What is being generated?](docs/07_WhatIsBeingGenerated.md)

## The Facet Ecosystem

Facet is modular and consists of several NuGet packages:

- **Facet**: The core source generator. Generates DTOs, projections, and mapping code.

- **Facet.Extensions**: Provider-agnostic extension methods for mapping and projecting (works with any LINQ provider, no EF Core dependency).

- **Facet.Extensions.EFCore**: Async extension methods for Entity Framework Core (requires EF Core 6+).

- **Facet.Mapping**: (Optional) Advanced static mapping configuration support for Facet.

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**Facet** — Define less, project more.