swaf/src/frontend/MailViewEngine.ts

import mjml2html from "mjml";

import MailError from "../mail/MailError.js";
import NunjucksViewEngine from "./NunjucksViewEngine.js";

export default class MailViewEngine extends NunjucksViewEngine {
    public getExtension(): string {
        return 'mnjk';
    }

    public async render(
        file: string,
        locals: Record<string, unknown>,
        textOnly: boolean = false,
    ): Promise<string> {
        locals.text = textOnly;
        const nunjucksResult = await super.render(file, locals);
        if (textOnly) return nunjucksResult;

        const mjmlResult = mjml2html(nunjucksResult, {});

        if (mjmlResult.errors.length > 0) {
            throw new MailError(`Error while parsing mail template ${file}: ${JSON.stringify(mjmlResult.errors, null, 4)}`);
        }

        return mjmlResult.html;
    }
}