ShippingCalculator

const flatRateCalculator = new ShippingCalculator({  code: 'flat-rate-calculator',  description: [{ languageCode: LanguageCode.en, value: 'Default Flat-Rate Shipping Calculator' }],  args: {    rate: {      type: 'int',      ui: { component: 'currency-form-input' },    },    taxRate: {      type: 'int',      ui: { component: 'number-form-input', suffix: '%' },    },  },  calculate: (ctx, order, args) => {    return {      price: args.rate,      taxRate: args.taxRate,      priceIncludesTax: ctx.channel.pricesIncludeTax,    };  },});

class ShippingCalculator<T extends ConfigArgs = ConfigArgs> extends ConfigurableOperationDef<T> {    constructor(config: ShippingCalculatorConfig<T>)}

interface ShippingCalculationResult {    price: number;    priceIncludesTax: boolean;    taxRate: number;    metadata?: Record<string, any>;}

type CalculateShippingFn<T extends ConfigArgs> = (    ctx: RequestContext,    order: Order,    args: ConfigArgValues<T>,    method: ShippingMethod,) => CalculateShippingFnResult