OrderInterceptor

An OrderInterceptor is a class which can be used to intercept and modify the behavior of order-related operations.

It does this by providing methods which are called whenever the contents of an order are about to get changed. These methods are able to prevent the operation from proceeding by returning a string error message.

Examples of use-cases for an OrderInterceptor include:

Preventing certain products from being added to the order based on some criteria, e.g. if the product is already in another active order.
Enforcing a minimum or maximum quantity of a given product in the order
Using a CAPTCHA to prevent automated order creation

Info

This is configured via the orderOptions.orderInterceptors property of your VendureConfig.

OrderInterceptors are executed when the following mutations are called:

addItemToOrder
adjustOrderLine
removeItemFromOrder

Additionally, if you are working directly with the OrderService, the following methods will trigger any registered OrderInterceptors:

addItemToOrder
addItemsToOrder
adjustOrderLine
adjustOrderLines
removeItemFromOrder
removeItemsFromOrder

When an OrderInterceptor is registered, it will be called in the order in which it was registered. If an interceptor method resolves to a string, the operation will be prevented and the string will be used as the error message.

When multiple interceptors are registered, the first interceptor to resolve to a string will prevent the operation from proceeding.

Errors returned by OrderInterceptors are surfaced to the GraphQL API as an OrderInterceptorError and can be queried like this:

Graphql

mutation AddItemToOrder($productVariantId: ID!, $quantity: Int!) {  addItemToOrder(productVariantId: $productVariantId, quantity: $quantity) {    ... on Order {      id      code      # ... other Order fields    }    ... on ErrorResult {      errorCode      message    }    ... on OrderInterceptorError {      interceptorError    }  }}

In the above example, the error message returned by the OrderInterceptor would be available in the interceptorError field.

Example: Min/max order quantity

Let's say we want to allow ProductVariants to specify the minimum or maximum amount which may be added to an order. We can define custom fields to store this information and then use this custom field value to prevent an order line from being added to the order if the quantity is below the minimum.

Example

import {  EntityHydrator,  Injector,  LanguageCode,  Order,  OrderInterceptor,  ProductVariant,  RequestContext,  TranslatorService,  VendurePlugin,  WillAddItemToOrderInput,  WillAdjustOrderLineInput,} from '@vendure/core';declare module '@vendure/core/dist/entity/custom-entity-fields' {  interface CustomProductVariantFields {    minOrderQuantity?: number;    maxOrderQuantity?: number;  }}// This OrderInterceptor enforces minimum and maximum order quantities on ProductVariants.export class MinMaxOrderInterceptor implements OrderInterceptor { private entityHydrator: EntityHydrator; private translatorService: TranslatorService; init(injector: Injector) {   this.entityHydrator = injector.get(EntityHydrator);   this.translatorService = injector.get(TranslatorService); } willAddItemToOrder(   ctx: RequestContext,   order: Order,   input: WillAddItemToOrderInput, ): Promise<void | string> | void | string {   const { productVariant, quantity } = input;   const min = productVariant.customFields?.minOrderQuantity;   const max = productVariant.customFields?.maxOrderQuantity;   if (min && quantity < min) {     return this.minErrorMessage(ctx, productVariant, min);   }   if (max && quantity > max) {     return this.maxErrorMessage(ctx, productVariant, max);   } } willAdjustOrderLine(   ctx: RequestContext,   order: Order,   input: WillAdjustOrderLineInput, ): Promise<void | string> | void | string {   const { orderLine, quantity } = input;   const min = orderLine.productVariant.customFields?.minOrderQuantity;   const max = orderLine.productVariant.customFields?.maxOrderQuantity;   if (min && quantity < min) {     return this.minErrorMessage(ctx, orderLine.productVariant, min);   }   if (max && quantity > max) {     return this.maxErrorMessage(ctx, orderLine.productVariant, max);   } } private async minErrorMessage(ctx: RequestContext, variant: ProductVariant, min: number) {   const variantName = await this.getTranslatedVariantName(ctx, variant);   return `Minimum order quantity for "${variantName}" is ${min}`; } private async maxErrorMessage(ctx: RequestContext, variant: ProductVariant, max: number) {   const variantName = await this.getTranslatedVariantName(ctx, variant);   return `Maximum order quantity for "${variantName}" is ${max}`; } private async getTranslatedVariantName(ctx: RequestContext, variant: ProductVariant) {   await this.entityHydrator.hydrate(ctx, variant, { relations: ['translations'] });   const translated = this.translatorService.translate(variant, ctx);   return translated.name; }}// This plugin enforces minimum and maximum order quantities on ProductVariants.// It adds two new custom fields to ProductVariant:// - minOrderQuantity// - maxOrderQuantity//// It also adds an OrderInterceptor which enforces these limits.@VendurePlugin({ configuration: config => { // Here we add the custom fields to the ProductVariant entity   config.customFields.ProductVariant.push({     type: 'int',     min: 0,     name: 'minOrderQuantity',     label: [{ languageCode: LanguageCode.en, value: 'Minimum order quantity' }],     nullable: true,   });   config.customFields.ProductVariant.push({     type: 'int',     min: 0,     name: 'maxOrderQuantity',     label: [{ languageCode: LanguageCode.en, value: 'Maximum order quantity' }],     nullable: true,   });   // Here we add the MinMaxOrderInterceptor to the orderInterceptors array   config.orderOptions.orderInterceptors.push(new MinMaxOrderInterceptor());   return config; },})export class OrderQuantityLimitsPlugin {}

Signature

interface OrderInterceptor extends InjectableStrategy {    willAddItemToOrder?(        ctx: RequestContext,        order: Order,        input: WillAddItemToOrderInput,    ): Promise<void | string> | void | string;    willAdjustOrderLine?(        ctx: RequestContext,        order: Order,        input: WillAdjustOrderLineInput,    ): Promise<void | string> | void | string;    willRemoveItemFromOrder?(        ctx: RequestContext,        order: Order,        orderLine: OrderLine,    ): Promise<void | string> | void | string;}

Extends: InjectableStrategy

willAddItemToOrder

method(ctx: RequestContext, order: Order, input: WillAddItemToOrderInput) => Promise<void | string> | void | string

Called when a new item is about to be added to the order, as in the addItemToOrder mutation or the addItemToOrder() / addItemsToOrder() method of the OrderService.

willAdjustOrderLine

method(ctx: RequestContext, order: Order, input: WillAdjustOrderLineInput) => Promise<void | string> | void | string

Called when an existing order line is about to be adjusted, as in the adjustOrderLine mutation or the adjustOrderLine() / adjustOrderLines() method of the OrderService.

willRemoveItemFromOrder

method(ctx: RequestContext, order: Order, orderLine: OrderLine) => Promise<void | string> | void | string

Called when an item is about to be removed from the order, as in the removeItemFromOrder mutation or the removeItemFromOrder() / removeItemsFromOrder() method of the OrderService.