Other features¶

Preserving parts of a TypeScript file¶

Since TypeGen 1.3, there is a possibility of preserving parts of a TypeScript file, so that they won’t be overridden when regenerating the file. This can be achieved with <custom-head> and <custom-body> tags specified in the comments, as shown below:

//<custom-head>
import { Foo } from "../bar";
//</custom-head>

export class Product {
    netPrice: number;
    vat: number;

    //<custom-body>
    get price(): number {
        return this.netPrice + this.vat;
    }
    //</custom-body>
}

This will keep both the extra import and the price property intact upon file regeneration.

Multiple code fragments can be tagged with <custom-head> or <custom-body> as well (however, multiple blocks are merged into one upon file generation):

export class Product {
    netPrice: number;
    vat: number;

    //<custom-body>
    get price(): number {
        return this.netPrice + this.vat;
    }
    //</custom-body>

    //<custom-body>
    get priceSpecified(): boolean {
        return this.netPrice !== undefined;
    }
    //</custom-body>
}

Note: //<custom-xyz> (followed by a new line) is the only acceptable format of a tag. The following will not work:

// <custom-xyz>
//<custom-xyz >
//<custom-xyz> some comments after this

<custom-head> and <custom-body> tags are case-insensitive, so e.g. <CUSTOM-HEAD> is also acceptable.

Deprecation note:

<custom-head> and <custom-body> tags are available since TypeGen 1.4.0. Prior to this version, the <keep-ts> tag was used for preserving parts of the type’s definition. The <keep-ts> tag will still work in versions higher than 1.3.0 (unless decided otherwise), however its use is deprecated since version 1.4.0.

Strict null checking¶

You can specify how C# nullable property/field types will be translated to TypeScript by default, by using the csNullableTranslation parameter (CLI or generator options). Available choices are:

type | null
type | undefined
type | null | undefined
type (not null and not undefined)

To override the default C# nullable types translation or to specify a type union for non-nullable types, you can use the following attributes on a property or field: TsNull, TsNotNull, TsUndefined, TsNotUndefined (you can find more information on these attributes in the TypeGen attributes section).

Adding files to a .NET framework project¶

This feature is only available in TypeGen CLI (not available in programmatical API, as the programmatical API doesn’t operate on a per-project level). When this option is selected, generated TS sources will automatically be added to a .NET Framework project in the chosen project folder. This feature is only available for .NET Framework projects (not .NET Core), because .NET Core projects don’t specify included files in the project file.

Creating TypeScript barrel files¶

Barrels are created by adding them to a generation spec (please visit the generation spec section for the details on how to add barrels). There is also a possibility to add a “global” barrel file by enabling the createIndexFile config option, however this option offers very limited functionality; also it’s deprecated and will be removed in the future.

Default values for TS properties based on the type¶

It is possible to generate default values for properties inside TS classes/interfaces, depending on the property type. The [TS type -> default value] mappings can be specified either in the defaultValuesForTypes CLI parameter or in the GeneratorOptions.DefaultValuesForTypes property.

Custom type mappings¶

TypeGen allows to override its default C# to TS type mappings or create new custom mappings. The way to define mappings is via either the customTypeMappings CLI parameter or the GeneratorOptions.CustomTypeMappings property.

Default exports¶

There is a possibility to use default exports instead of named exports when generating TypeScript types. This feature can be enabled/disabled globally, by setting the useDefaultExport CLI parameter or the GeneratorOptions.UseDefaultExport property, or a one-time opt-in/out can be used with either the TsDefaultExportAttribute or the DefaultExport(bool) generation spec method.