feat(cart): Item tax lines + shipping method tax lines (#6136)

packages/cart/src/models/line-item-tax-line.ts

@@ -1,15 +1,25 @@
 import { generateEntityId } from "@medusajs/utils"
-import { BeforeCreate, Entity, ManyToOne, OnInit } from "@mikro-orm/core"
+import {
+  BeforeCreate,
+  Entity,
+  ManyToOne,
+  OnInit,
+  Property,
+} from "@mikro-orm/core"
 import LineItem from "./line-item"
 import TaxLine from "./tax-line"
 
 @Entity({ tableName: "cart_line_item_tax_line" })
 export default class LineItemTaxLine extends TaxLine {
   @ManyToOne(() => LineItem, {
-    joinColumn: "line_item",
-    fieldName: "line_item_id",
+    onDelete: "cascade",
+    nullable: true,
+    index: "IDX_tax_line_item_id",
   })
-  line_item: LineItem
+  item: LineItem | null
+
+  @Property({ columnType: "text" })
+  item_id: string
 
   @BeforeCreate()
   onCreate() {

packages/cart/src/models/line-item.ts

@@ -110,18 +110,14 @@ export default class LineItem {
   @Check({ expression: "unit_price >= 0" }) // TODO: Validate that numeric types work with the expression
   unit_price: number
 
-  @OneToMany(() => LineItemTaxLine, (taxLine) => taxLine.line_item, {
+  @OneToMany(() => LineItemTaxLine, (taxLine) => taxLine.item, {
     cascade: [Cascade.REMOVE],
   })
   tax_lines = new Collection<LineItemTaxLine>(this)
 
-  @OneToMany(
-    () => LineItemAdjustment,
-    (adjustment) => adjustment.item,
-    {
-      cascade: [Cascade.REMOVE],
-    }
-  )
+  @OneToMany(() => LineItemAdjustment, (adjustment) => adjustment.item, {
+    cascade: [Cascade.REMOVE],
+  })
   adjustments = new Collection<LineItemAdjustment>(this)
 
   /** COMPUTED PROPERTIES - START */

packages/cart/src/models/shipping-method-tax-line.ts

@@ -1,15 +1,25 @@
 import { generateEntityId } from "@medusajs/utils"
-import { BeforeCreate, Entity, ManyToOne, OnInit } from "@mikro-orm/core"
+import {
+  BeforeCreate,
+  Entity,
+  ManyToOne,
+  OnInit,
+  Property,
+} from "@mikro-orm/core"
 import ShippingMethod from "./shipping-method"
 import TaxLine from "./tax-line"
 
 @Entity({ tableName: "cart_shipping_method_tax_line" })
 export default class ShippingMethodTaxLine extends TaxLine {
   @ManyToOne(() => ShippingMethod, {
-    joinColumn: "shipping_method",
-    fieldName: "shipping_method_id",
+    onDelete: "cascade",
+    nullable: true,
+    index: "IDX_tax_line_shipping_method_id",
   })
-  shipping_method: ShippingMethod
+  shipping_method: ShippingMethod | null
+
+  @Property({ columnType: "text" })
+  shipping_method_id: string
 
   @BeforeCreate()
   onCreate() {

packages/cart/src/models/tax-line.ts

@@ -1,6 +1,6 @@
 import { PrimaryKey, Property } from "@mikro-orm/core"
 
-/** 
+/**
  * As per the Mikro ORM docs, superclasses should use the abstract class definition
  * Source: https://mikro-orm.io/docs/inheritance-mapping
  */
@@ -17,7 +17,7 @@ export default abstract class TaxLine {
   @Property({ columnType: "text" })
   code: string
 
-  @Property({ columnType: "numeric" })
+  @Property({ columnType: "numeric", serializer: Number })
   rate: number
 
   @Property({ columnType: "text", nullable: true })