Date Handling

Work with automatic date transformation features in ng-openapi.

Automatic Date Transformation

Configuration

// openapi.config.ts
const config: GeneratorConfig = {
    options: {
        dateType: "Date", // Enables automatic transformation
    },
};

Generated Models

// Generated interface with Date type
interface User {
    id: number;
    name: string;
    createdAt: Date; // Automatically transformed from ISO string
    updatedAt: Date;
}

Usage

export class UsersComponent {
    private readonly usersService = inject(UsersService);

    loadUser(id: number) {
        this.usersService.getUserById(id).subscribe((user) => {
            // createdAt is already a Date object
            console.log(user.createdAt.getFullYear());
            console.log(user.createdAt.toLocaleDateString());
        });
    }
}

String Dates

Configuration

// openapi.config.ts
const config: GeneratorConfig = {
    options: {
        dateType: "string", // No transformation
    },
};

Generated Models

// Generated interface with string type
interface User {
    id: number;
    name: string;
    createdAt: string; // ISO string format
    updatedAt: string;
}

Usage

export class UsersComponent {
    loadUser(id: number) {
        this.usersService.getUserById(id).subscribe((user) => {
            // Convert manually when needed
            const createdDate = new Date(user.createdAt);
            console.log(createdDate.getFullYear());
        });
    }
}

Date Transformer Interceptor

Disable Transformation

// Disable in provider
provideDefaultClient({
    basePath: "https://api.example.com",
    enableDateTransform: false,
});

Manual Setup

DateInterceptor is class-based, so it is registered through the HTTP_INTERCEPTORS multi-provider (withInterceptors only accepts functional interceptors):

import { HTTP_INTERCEPTORS, provideHttpClient, withInterceptorsFromDi } from "@angular/common/http";
import { DateInterceptor } from "./client/utils/date-transformer";

export const appConfig: ApplicationConfig = {
    providers: [
        provideHttpClient(withInterceptorsFromDi()),
        { provide: HTTP_INTERCEPTORS, useClass: DateInterceptor, multi: true },
    ],
};

Which Strings Are Detected as Dates?

The interceptor only converts strings matching a strict full ISO 8601 date-time pattern (ISO_DATE_REGEX), so bare years or numeric IDs are never accidentally turned into Date objects. The exact pattern and all recognized formats are documented in the Date Transformer reference.

Custom Date Regex

If your API returns a format the default pattern doesn't cover, pass your own regex via the provider — no need to copy date-transformer.ts:

provideDefaultClient({
    basePath: "https://api.example.com",
    // Use any pattern you like; it overrides ISO_DATE_REGEX
    dateTransformRegex: /your-custom-pattern/,
});

transformDates and DateInterceptor also accept the regex directly, so you can reuse them in a manual interceptor setup:

new DateInterceptor(/your-custom-regex/);
transformDates(responseBody, /your-custom-regex/);

Resources

• Date Transformer reference — recognized formats, generated source, manual setup
• JavaScript Date ↗️
• Angular HTTP Interceptors ↗️