feat(link-modules,modules-sdk, utils, types, products) - Remote Link and Link modules (#4695)

What:
- Definition of all Modules links
- `link-modules` package to manage the creation of all pre-defined link or custom ones

```typescript
import { initialize as iniInventory } from "@medusajs/inventory";
import { initialize as iniProduct } from "@medusajs/product";

import {
  initialize as iniLinks,
  runMigrations as migrateLinks
} from "@medusajs/link-modules";

await Promise.all([iniInventory(), iniProduct()]);


await migrateLinks(); // create tables based on previous loaded modules

await iniLinks(); // load link based on previous loaded modules

await iniLinks(undefined, [
  {
    serviceName: "product_custom_translation_service_link",
    isLink: true,
    databaseConfig: {
      tableName: "product_transalations",
    },
    alias: [
      {
        name: "translations",
      },
    ],
    primaryKeys: ["id", "product_id", "translation_id"],
    relationships: [
      {
        serviceName: Modules.PRODUCT,
        primaryKey: "id",
        foreignKey: "product_id",
        alias: "product",
      },
      {
        serviceName: "custom_translation_service",
        primaryKey: "id",
        foreignKey: "translation_id",
        alias: "transalation",
        deleteCascade: true,
      },
    ],
    extends: [
      {
        serviceName: Modules.PRODUCT,
        relationship: {
          serviceName: "product_custom_translation_service_link",
          primaryKey: "product_id",
          foreignKey: "id",
          alias: "translations",
          isList: true,
        },
      },
      {
        serviceName: "custom_translation_service",
        relationship: {
          serviceName: "product_custom_translation_service_link",
          primaryKey: "product_id",
          foreignKey: "id",
          alias: "product_link",
        },
      },
    ],
  },
]); // custom links
```

Remote Link

```typescript
import { RemoteLink, Modules } from "@medusajs/modules-sdk";

// [...] initialize modules and links

const remoteLink = new RemoteLink();

// upsert the relationship
await remoteLink.create({ // one (object) or many (array)
  [Modules.PRODUCT]: {
    variant_id: "var_abc",
  },
  [Modules.INVENTORY]: {
    inventory_item_id: "iitem_abc",
  },
  data: { // optional additional fields
    required_quantity: 5
  }
});

// dismiss (doesn't cascade)
await remoteLink.dismiss({ // one (object) or many (array)
  [Modules.PRODUCT]: {
    variant_id: "var_abc",
  },
  [Modules.INVENTORY]: {
    inventory_item_id: "iitem_abc",
  },
});

// delete
await remoteLink.delete({
  // every key is a module
  [Modules.PRODUCT]: {
    // every key is a linkable field
    variant_id: "var_abc", // single or multiple values
  },
});

// restore
await remoteLink.restore({
  // every key is a module
  [Modules.PRODUCT]: {
    // every key is a linkable field
    variant_id: "var_abc", // single or multiple values
  },
});

```

Co-authored-by: Riqwan Thamir <5105988+riqwan@users.noreply.github.com>

packages/link-modules/src/utils/compose-link-name.ts

@@ -0,0 +1,9 @@
+import { lowerCaseFirst, toPascalCase } from "@medusajs/utils"
+
+export const composeLinkName = (...args) => {
+  return lowerCaseFirst(toPascalCase(composeTableName(...args.concat("link"))))
+}
+
+export const composeTableName = (...args) => {
+  return args.map((name) => name.replace(/(_id|Service)$/gi, "")).join("_")
+}

packages/link-modules/src/utils/generate-entity.ts

@@ -0,0 +1,110 @@
+import { JoinerRelationship, ModuleJoinerConfig } from "@medusajs/types"
+import {
+  SoftDeletableFilterKey,
+  mikroOrmSoftDeletableFilterOptions,
+  simpleHash,
+} from "@medusajs/utils"
+
+import { EntitySchema } from "@mikro-orm/core"
+import { composeTableName } from "./compose-link-name"
+
+function getClass(...properties) {
+  return class LinkModel {
+    constructor(...values) {
+      properties.forEach((name, idx) => {
+        this[name] = values[idx]
+      })
+    }
+  }
+}
+
+export function generateEntity(
+  joinerConfig: ModuleJoinerConfig,
+  primary: JoinerRelationship,
+  foreign: JoinerRelationship
+) {
+  const fieldNames = primary.foreignKey.split(",").concat(foreign.foreignKey)
+
+  const tableName =
+    joinerConfig.databaseConfig?.tableName ??
+    composeTableName(
+      primary.serviceName,
+      primary.foreignKey,
+      foreign.serviceName,
+      foreign.foreignKey
+    )
+
+  const fields = fieldNames.reduce((acc, curr) => {
+    acc[curr] = {
+      type: "string",
+      nullable: false,
+      primary: true,
+    }
+    return acc
+  }, {})
+
+  const extraFields = joinerConfig.databaseConfig?.extraFields ?? {}
+
+  for (const column in extraFields) {
+    fieldNames.push(column)
+
+    fields[column] = {
+      type: extraFields[column].type,
+      nullable: !!extraFields[column].nullable,
+      defaultRaw: extraFields[column].defaultValue,
+      ...(extraFields[column].options ?? {}),
+    }
+  }
+
+  const hashTableName = simpleHash(tableName)
+
+  return new EntitySchema({
+    class: getClass(
+      ...fieldNames.concat("created_at", "updated_at", "deleted_at")
+    ) as any,
+    tableName,
+    properties: {
+      id: {
+        type: "string",
+        nullable: false,
+      },
+      ...fields,
+      created_at: {
+        type: "Date",
+        nullable: false,
+        defaultRaw: "CURRENT_TIMESTAMP",
+      },
+      updated_at: {
+        type: "Date",
+        nullable: false,
+        defaultRaw: "CURRENT_TIMESTAMP",
+      },
+      deleted_at: { type: "Date", nullable: true },
+    },
+    filters: {
+      [SoftDeletableFilterKey]: mikroOrmSoftDeletableFilterOptions,
+    },
+    indexes: [
+      {
+        properties: ["id"],
+        name: "IDX_id_" + hashTableName,
+      },
+      {
+        properties: primary.foreignKey.split(","),
+        name:
+          "IDX_" +
+          primary.foreignKey.split(",").join("_") +
+          "_" +
+          hashTableName,
+      },
+      {
+        properties: foreign.foreignKey,
+        name: "IDX_" + foreign.foreignKey + "_" + hashTableName,
+      },
+      {
+        properties: ["deleted_at"],
+        name: "IDX_deleted_at_" + hashTableName,
+      },
+    ],
+  })
+}

packages/link-modules/src/utils/index.ts

@@ -0,0 +1,12 @@
+import { MODULE_RESOURCE_TYPE } from "@medusajs/types"
+
+export * from "./compose-link-name"
+export * from "./generate-entity"
+
+export function shouldForceTransaction(target: any): boolean {
+  return target.moduleDeclaration?.resources === MODULE_RESOURCE_TYPE.ISOLATED
+}
+
+export function doNotForceTransaction(): boolean {
+  return false
+}