https://github.com/nenonaninu/tapper
A Tool Transpiling C# Type into TypeScript Type. (Support JSON & MessagePack Serialization)
https://github.com/nenonaninu/tapper
c-sharp csharp generator transpiler typescript
Last synced: about 1 year ago
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A Tool Transpiling C# Type into TypeScript Type. (Support JSON & MessagePack Serialization)
- Host: GitHub
- URL: https://github.com/nenonaninu/tapper
- Owner: nenoNaninu
- License: mit
- Created: 2022-03-30T12:57:51.000Z (about 4 years ago)
- Default Branch: main
- Last Pushed: 2025-03-12T03:18:52.000Z (over 1 year ago)
- Last Synced: 2025-05-16T04:03:16.973Z (about 1 year ago)
- Topics: c-sharp, csharp, generator, transpiler, typescript
- Language: C#
- Homepage:
- Size: 519 KB
- Stars: 110
- Watchers: 7
- Forks: 8
- Open Issues: 4
-
Metadata Files:
- Readme: README.md
- License: LICENSE
Awesome Lists containing this project
README
# Tapper
[](https://www.nuget.org/packages/Tapper.Attributes)
[](https://github.com/nenoNaninu/Tapper/actions/workflows/build-and-test.yaml)
Tapper is a library/CLI tool to transpile C# type (class, struct, record, enum) into TypeScript type (type, enum).
Using this tool can reduce serialization bugs (type mismatch, typos, etc.) and make TypeScript code easily follow changes in C# code.
## Table of Contents
- [Packages](#packages)
- [Install Using .NET Tool](#install-using-net-tool)
- [Getting Started](#getting-started)
- [Transpilation Rules](#transpilation-rules)
- [Built-in Supported Types](#built-in-supported-types)
- [C# Namespace](#c-namespace)
- [Nesting Types](#nesting-types)
- [Options](#options)
- [Naming Style](#naming-style)
- [Enum Style](#enum-style)
- [Serializer](#serializer)
- [MessagePack](#messagepack)
- [Serializer Attributes Support](#serializer-attributes-support)
- [JSON](#json)
- [MessagePack](#messagepack-1)
- [Transpile the Types Contained in Referenced Assemblies](#transpile-the-types-contained-in-referenced-assemblies)
- [Analyzer](#analyzer)
- [Unity Support](#unity-support)
- [Related Work](#related-work)
## Packages
- [Tapper.Attributes](https://www.nuget.org/packages/Tapper.Attributes/)
- [Tapper.Analyzer](https://www.nuget.org/packages/Tapper.Analyzer/)
- [Tapper.Generator](https://www.nuget.org/packages/Tapper.Generator/) (.NET Tool)
### Install Using .NET Tool
Use `Tapper.Generator`(CLI Tool) to generate TypeScript type from C# type.
`Tapper.Generator` can be easily installed using .NET Global Tools.
You can use the installed tools with the command `tapper`.
```bash
# install
# Tapper CLI (dotnet tool) requires .NET 7 or .NET 8, but your app TFM can use .NET 6, etc.
$ dotnet tool install --global Tapper.Generator
$ tapper help
# update
$ dotnet tool update --global Tapper.Generator
```
## Getting Started
First, add the following packages to your project.
Tapper.Analyzer is optional, but recommended.
```bash
$ dotnet add package Tapper.Attributes
$ dotnet add package Tapper.Analyzer (optional, but recommended.)
```
Next, apply the `[TranspilationSource]` Attribute to the C# type definition.
```cs
using Tapper;
namespace SampleNamespace;
[TranspilationSource] // <- Add attribute!
public class SampleType
{
public List? List { get; }
public int Value { get; }
public Guid Id { get; }
public DateTime DateTime { get; }
}
```
Then execute the command as follows.
```bash
$ tapper --project path/to/XXX.csproj --output outdir
```
TypeScript source code is generated in the directory specified by `--output`.
In this example, TypeScript source code named `outdir/SampleNamespace.ts` is generated.
The contents of the generated code is as follows.
```ts
/* eslint-disable */
/** Transpiled from SampleNamespace.SampleType */
export type SampleType = {
/** Transpiled from System.Collections.Generic.List? */
list?: number[];
/** Transpiled from int */
value: number;
/** Transpiled from System.Guid */
id: string;
/** Transpiled from System.DateTime */
dateTime: (Date | string);
}
```
## Transpilation Rules
Tapper transpile C# types (class, struct, record, enum) to TypeScript types (type, enum).
When transpiling class, struct, and record, only `public` fields and properties are transpiled.
### Built-in Supported Types
| C# | TypeScript | Description |
| ---- | ---- | ---- |
| bool | boolean |
| byte | number |
| sbyte | number |
| char | string or number | JSON: `string`, MessagePack `number`. |
| decimal | number |
| double | number |
| float | number |
| int | number |
| uint | number |
| long | number |
| ulong | number |
| short | number |
| ushort | number |
| object | any |
| string | string |
| Uri | string |
| Guid | string | Compatible with TypeScript's `crypto.randomUUID()`. |
| DateTime | `(Date \| string)` or `Date` | Json: `(Date \| string)`, MessagePack: `Date`. |
| DateTimeOffset | `(Date \| string)` or `[Date, number]` | Json: `(Date \| string)`, MessagePack: `[Date, number]`. note [#41](https://github.com/nenoNaninu/Tapper/pull/41) |
| TimeSpan | `string` or `number` | Json: `string`, MessagePack: `number`. |
| System.Nullable\| (T \| undefined) |
| byte[] | string or Uint8Array | JSON: `string` (base64), MessagePack `Uint8Array`. |
| T[] | T[] |
| System.Array | any[] | ❌ System.Text.Json |
| ArraySegment\ | T[] | ❌ System.Text.Json |
| List\ | T[] |
| LinkedList\ | T[] |
| Queue\ | T[] |
| Stack\ | T[] |
| HashSet\ | T[] |
| IEnumerable\ | T[] |
| IReadOnlyCollection\ | T[] |
| ICollection\ | T[] |
| IList\ | T[] |
| ISet\ | T[] |
| Dictionary | Partial> |
| IDictionary | Partial> |
| IReadOnlyDictionary | Partial> |
| Tuple | [T1, T2, ...] | ❌ System.Text.Json |
### C# Namespace
C# namespace is mapped to the filename of the generated TypeScript code.
```cs
namespace SampleNamespace;
[TranspilationSource]
record Xxx();
```
For example, given the above C# code, TypeScript code with the file name `SampleNamespace.ts` is generated.
### Nesting Types
It doesn't matter if the user-defined types are nested.
For example, consider the following C# code.
Apply `[TranspilationSource]` Attribute to all types to be transpiled.
If you add an analyzer package, you can avoid forgetting to apply `[TranspilationSource]`.
```cs
#nullable enable
using System.Text.Json.Serialization;
using Tapper;
namespace Space1
{
[TranspilationSource]
public class CustomType1
{
public int Value;
public Guid Id;
[JsonIgnore]
public string Foo;
}
namespace Sub
{
[TranspilationSource]
public enum MyEnum
{
Zero = 0,
One = 1,
Two = 1 << 1,
Four = 1 << 2,
}
}
}
namespace Space2
{
[TranspilationSource]
public record CustomType3(float Value, DateTime ReleaseDate);
}
namespace Space3
{
using Space1;
using Space1.Sub;
using Space2;
[TranspilationSource]
public class NastingNamespaceType
{
public CustomType1? Value { get; set; }
public MyEnum MyEnumValue { get; set; }
[JsonPropertyName("list")]
public List MyList { get; set; } = new();
}
}
```
The following TypeScript code is generated.
- Space1.ts
```ts
/** Transpiled from Space1.CustomType1 */
export type CustomType1 = {
/** Transpiled from int */
value: number;
/** Transpiled from System.Guid */
id: string;
}
```
- Space1.Sub.ts
```ts
/** Transpiled from Space1.Sub.MyEnum */
export enum MyEnum {
Zero = 0,
One = 1,
Two = 2,
Four = 4,
}
```
- Space2.ts
```ts
/** Transpiled from Space2.CustomType3 */
export type CustomType3 = {
/** Transpiled from float */
value: number;
/** Transpiled from System.DateTime */
name: (Date | string);
}
```
- Space3.ts
```ts
import { CustomType1 } from './Space1';
import { MyEnum } from './Space1.Sub';
import { CustomType3 } from './Space2';
/** Transpiled from Space3.NastingNamespaceType */
export type NastingNamespaceType = {
/** Transpiled from Space1.CustomType1? */
value?: CustomType1;
/** Transpiled from Space1.Sub.MyEnum */
myEnumValue: MyEnum;
/** Transpiled from System.Collections.Generic.List */
list: CustomType3[];
}
```
## Options
### Naming Style
You can select `camelCase`, `PascalCase`, or `none` for the property name of the generated TypeScript type.
For `none`, the property name in C# is used.
The default is the standard naming style for TypeScript.
```bash
$ tapper --project path/to/Xxx.csproj --output outdir --naming-style camelCase
```
### Enum Style
There are options for enum transpiling.
You can select `Value` (default), `Name`, `NameCamel`, `NamePascal`, `Union`, `UnionCamel`, or `UnionPascal`.
If you use this option, be careful with the serializer options.
For example, `System.Text.Json` serializes an enum as a integer by default (not string).
To serialize an enum as a string, you must pass `JsonStringEnumConverter` as an option to `JsonSerializer`.
```bash
$ tapper --project path/to/Xxx.csproj --output outdir --enum value
$ tapper --project path/to/Xxx.csproj --output outdir --enum name
$ tapper --project path/to/Xxx.csproj --output outdir --enum union
```
```cs
// C# source
[TranspilationSource]
public enum MyEnum
{
Zero = 0,
One = 1,
Two = 1 << 1,
Four = 1 << 2,
}
```
```ts
// Generated TypeScript
// --enum value (default)
export enum MyEnum {
Zero = 0,
One = 1,
Two = 2,
Four = 4,
}
// --enum name
export enum MyEnum {
Zero = "Zero",
One = "One",
Two = "Two",
Four = "Four",
}
// --enum union
export type MyEnum = "Zero" | "One" | "Two" | "Four";
// --enum unionCamel
export type MyEnum = "zero" | "one" | "two" | "four";
```
### Serializer
The TypeScript code generated by Tapper is supposed to be serialized/deserialized with `json` or` MessagePack`.
And the appropriate type is slightly different depending on the serializer.
You can specify which one to use by passing the `--serializer` option.
The default is `json`.
```bash
$ tapper --project path/to/Xxx.csproj --output outdir --serializer MessagePack --naming-style none
```
Also, it is supposed that the following serializers are used.
- Json
- C# : System.Text.Json
- TypeScript : JSON.stringify()
- MessagePack
- C# : [MessagePack-CSharp](https://github.com/neuecc/MessagePack-CSharp)
- TypeScript : [msgpack-javascript](https://github.com/msgpack/msgpack-javascript)
#### MessagePack
If you use [MessagePack-CSharp](https://github.com/neuecc/MessagePack-CSharp) for the serializer, be careful how you apply the `[MessagePackObject]` Attribute.
It is recommended to use `[MessagePackObject(true)]`.
Also, in that case, set `--naming-style` to `none`.
```bash
$ tapper --project path/to/Xxx.csproj --output outdir --serializer MessagePack --naming-style none
```
```cs
[MessagePackObject(true)] // <- use this!
public class SampleType
{
public Guid Id { get; set; }
public int Value { get; set; }
}
```
### Serializer Attributes Support
Tapper reflects JSON and MessagePack serializer attributes in the output TypeScript code.
Support attributes:
- `System.Text.Json.Serialization`
- `[JsonPropertyName("string")]`
- `[JsonIgnore]`
- `MessagePack`
- `[Key("string")]`
- `[IgnoreMember]`
#### JSON
```cs
// input C# code
// --serializer json
namespace Readme;
[TranspilationSource]
public class Type1
{
[JsonIgnore]
public required int Value { get; init; }
public required string Name { get; init; }
}
[TranspilationSource]
public class Type2
{
[JsonPropertyName("Foo")]
public required int Value { get; init; }
public required string Name { get; init; }
}
```
```ts
// output TypeScript code
/** Transpiled from Readme.Type1 */
export type Type1 = {
/** Transpiled from string */
name: string;
}
/** Transpiled from Readme.Type2 */
export type Type2 = {
/** Transpiled from int */
Foo: number;
/** Transpiled from string */
name: string;
}
```
#### MessagePack
```cs
// input C# code
// --serializer MessagePack --naming-style none
namespace Readme;
[TranspilationSource]
public class Type3
{
[IgnoreMember]
public required Value { get; init; }
public required string Name { get; init; }
}
[TranspilationSource]
public class Type4
{
[Key("Bar")]
public required int Value { get; init; }
public required string Name { get; init; }
}
```
```ts
// output TypeScript code
/** Transpiled from Readme.Type3 */
export type Type3 = {
/** Transpiled from string */
Name: string;
}
/** Transpiled from Readme.Type4 */
export type Type4 = {
/** Transpiled from int */
Bar: number;
/** Transpiled from string */
Name: string;
}
```
### Transpile the Types Contained in Referenced Assemblies
By default, only types defined in the project specified by the `--project` option are targeted for transpiling.
By passing the `--asm true` option, types contained in project/package reference assemblies will also be targeted for transpiling.
```bash
$ tapper --project path/to/Xxx.csproj --output outdir --asm true
```
## Analyzer
Tapper has some rules. You can easily follow those rules by adding `Tapper.Analyzer`.
- If the fields and property types contained in the type to which `[TranspilationSource]` applies are user-defined types, you must also apply `[TranspilationSource]` to those types.
- You cannot apply `[TranspilationSource]` to Generic type.
## Unity Support
For Unity projects, first, copy and paste the [TranspilationSourceAttribute.cs](/src/Tapper.Attributes/TranspilationSourceAttribute.cs) into your project.
Then apply `[TranspilationSource]` to types you want to transpile.
Next, a file named `Assembly-CSharp.csproj` is generated by Unity.
It is in the same hierarchy as Assets.
Use this project file as an argument to `--project`.
```bash
$ tapper --project path/to/Assembly-CSharp.csproj --output outdir
```
## Related Work
- [nenoNaninu/TypedSignalR.Client.TypeScript](https://github.com/nenoNaninu/TypedSignalR.Client.TypeScript)
- TypeScript source generator to provide strongly typed SignalR clients by analyzing C# type definitions.