T4TS

T4 template to generate TypeScript interface definitions.

Usage

1. Install the NuGet package (https://nuget.org/packages/T4TS).

2. Decoreate any C# class that you want to generate an interface for, with the TypeScriptInterfaceAttribute (in the T4TS namespace).

3. Run the T4TS.tt-file (right-click and select Run custom tool).

4. The generated file T4TS.d.ts will now contain the interfaces that can be used in your TypeScript files.

Examples

C# classes:

[TypeScriptInterface]
public class MyModel
{
    public int Number { get; set; }
    public string Name { get; set; }
    public ReferencedModel Ref { get; set; }
}

[TypeScriptInterface]
public class ReferencedModel
{
    public double Fraction { get; set; }
    public int[] Digits { get; set; }
}

Resulting T4TS.d.ts:

module T4TS {
    export interface MyModel {
        Number: number;
        Name: string;
        Ref: ReferencedModel;
    }
    export interface ReferencedModel {
        Fraction: number;
        Digits: number[];
    }
}

This interface can now be used in your TypeScript files:

/// <reference path="T4TS.d.ts" />
class Test {
    constructor () {
        // Make an AJAX post and get some data from the server.
        // In the callback, you can specify that the data is of a certain type:
        $.post('./example', {}, (data: T4TS.MyModel) => {
            // Intellisense support for the properties:
            alert(data.Number.toString());
            alert(data.Ref.Digits[0].toString());
        });
    }
}

Specifications

• Only public properties are considered

• Right now, System.DateTime is considered a string in the type translation. The main reason is that the JSON serialization in .NET MVC will typically serialize a DateTime as "\/Date(ticks)\/"

• The type translation works like this, from C# => TypeScript, for each property:

  • Built-in numeric type (int, double, float, etc.) => number
  • string => string
  • Nullable<T> => T?
  • A class marked with [TypeScriptInterface] => lookup the generated TypeScript name
  • Otherwise => any
  • For Collection<T>, List<T>, IList<T> and T[] => lookup type for T as above, and return T[].

• Inheritance of interfaces is supported. If Bar inherits Foo in C# and both are marked with the TypeScriptInterfaceAttribute, the generated interface would be interface Bar extends Foo {....

Customize the generated interfaces

The attribute TypeScriptInterfaceAttribute is set on C# classes, and has the following properties:

• Name: Specifies the name of the interface (default is the class name).
• Module: Specifies the module of the interface (default T4TS).
• NamePrefix: If specified, the interface name will be prefixed with this string.

The attribute TypeScriptMemberAttribute can be set on the properties of a C# class, and has the following properties:

• Name: Specifies the name of the member (default is the property name).
• Optional: Specifies whether this member should be optional, ie. member?: type instead of member: type.
• Type: Specifies the type of the member (default is to do type translation of the property).
• CamelCase: If set to true, the first character of the member name will be lower cased.

Default settings

There are a couple of default settings that can be specified in the T4TS.tt.settings.t4 file.

• DefaultModule: The default module name of an interfaces (if not specified by TypeScriptInterfaceAttribute). Default is "T4TS".
• DefaultOptional: The default value for the Optional flag for TypeScriptMemberAttribute. Default is false.
• DefaultCamelCaseMemberNames: The default value for the CamelCase flag for TypeScriptMemberAttribute. Default is false.
• DefaultInterfaceNamePrefix: The default value for the NamePrefix flag for TypeScriptInterfaceAttribute. Default is "".
• CompatibilityVersion: The version of Typescript that is targeted. This will help handling breaking changes in the language grammar and/or compiler. Default (right now) is 0.9.1.1.

Known problems

TextTransformation fails:

I have experienced some error message the first time the T4TS package is installed via NuGet. However, if you build the project, or run the .tt-file, the error message disappears.

License

Apache License, Version 2.0

Thanks to T4MVC, which has been the inspiration. I also learned how to use the .tt-stuff from reading the source, and using part of the source code from T4MVC.