04886ea122
* docs: rename property when defining a list link * added note about static directory * remove note about static directory
129 lines
3.6 KiB
Plaintext
129 lines
3.6 KiB
Plaintext
export const metadata = {
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title: `${pageNumber} Module Link`,
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}
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# {metadata.title}
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In this chapter, you’ll learn what a module link is.
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<Note type="soon" title="In Development">
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Module links are in active development.
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</Note>
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## What is a Module Link?
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A module link forms an association between two data models of different modules, while maintaining module isolation.
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You can then retrieve data across the linked modules, and manage their linked records.
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---
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## Prerequisite: isQueryable Configuration
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Before you define a module link, you must enable the `isQueryable` configuration of the module.
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For example:
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```js
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module.exports = defineConfig({
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// ...
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modules: {
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helloModuleService: {
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resolve: "./modules/hello",
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definition: {
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isQueryable: true,
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},
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},
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},
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})
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```
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---
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## How to Define a Module Link?
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### 1. Create Link File
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Links are defined in a TypeScript or JavaScript file under the `src/links` directory. The file defines the link using the `defineLink` function imported from `@medusajs/utils` and exports it.
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For example:
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export const highlights = [
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["6", "linkable", "Special `linkable` property that holds the linkable data models of `HelloModule`."],
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["7", "linkable", "Special `linkable` property that holds the linkable data models of `ProductModule`."],
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]
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```ts title="src/links/hello-product.ts" highlights={highlights}
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import HelloModule from "../modules/hello"
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import ProductModule from "@medusajs/product"
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import { defineLink } from "@medusajs/utils"
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export default defineLink(
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HelloModule.linkable.myCustom,
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ProductModule.linkable.product
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)
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```
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The `defineLink` function accepts as parameters the link configurations of each module's data model. A module has a special `linkable` property that holds these configurations for its data models.
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In this example, you define a module link between the `hello` module's `MyCustom` data model and the Product Module's `Product` data model.
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### 2. Run Migrations
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Medusa stores links as pivot tables in the database, so you must run migrations after defining a link:
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```bash
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npx medusa migrations run
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```
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---
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## Define a List Link
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By default, the defined link establishes a one-to-one relation: a record of a data model is linked to one record of the other data model.
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To specify that a data model can have multiple of its records linked to the other data model's record, use the `isList` option.
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For example:
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```ts
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import HelloModule from "../modules/hello"
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import ProductModule from "@medusajs/product"
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import { defineLink } from "@medusajs/utils"
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export default defineLink(
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{
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linkable: HelloModule.linkable.myCustom,
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isList: true
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},
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ProductModule.linkable.product
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)
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```
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In this case, you pass an object of configuration as a parameter instead. The object accepts the following properties:
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- `linkable`: The data model's link configuration.
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- `isList`: Whether multiple records can be linked to one record of the other data model.
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In this example, a record of `product` can be linked to more than one record of `myCustom`.
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---
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## Extend Data Models with Module Links
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Module links are most useful when you want to add properties to a data model of another module.
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For example, to add custom properties to the `Product` data model of the Product Module, you:
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1. Create a module.
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2. Create in the module a data model that holds the custom properties you want to add to the `Product` data model.
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2. Define a module link that links your module to the Product Module.
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Then, in the next chapters, you'll learn how to:
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- Link each product to a record of your data model.
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- Retrieve your data model's properties when you retrieve products.
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