feat(medusa, utils): Allow object feature flags (#4701)

Feature flags can be set as follows:

**Environment variables**
```
MEDUSA_FF_ANALYTICS=true
MEDUSA_FF_WORKFLOWS=createProducts,addShippingMethods
```

**Project config**
```
{
  featureFlags: {
    analytics: true,
    workflows: {
      createProducts: true,
      addShippingMethods: true,
    }
  }
}
```

packages/utils/src/common/build-query.ts

@@ -1,5 +1,8 @@
 // Those utils are used in a typeorm context and we can't be sure that they can be used elsewhere
 
+import { objectFromStringPath } from "./object-from-string-path"
+
+
 type Order = {
   [key: string]: "ASC" | "DESC" | Order
 }
@@ -20,79 +23,8 @@ export function buildRelations(relationCollection: string[]): Relations {
   return buildRelationsOrSelect(relationCollection)
 }
 
-/**
- * Convert a collection of dot string into a nested object
- * @example
- * input: [
- *    order,
- *    order.items,
- *    order.swaps,
- *    order.swaps.additional_items,
- *    order.discounts,
- *    order.discounts.rule,
- *    order.claims,
- *    order.claims.additional_items,
- *    additional_items,
- *    additional_items.variant,
- *    return_order,
- *    return_order.items,
- *    return_order.shipping_method,
- *    return_order.shipping_method.tax_lines
- * ]
- * output: {
- *   "order": {
- *     "items": true,
- *     "swaps": {
- *       "additional_items": true
- *     },
- *     "discounts": {
- *       "rule": true
- *     },
- *     "claims": {
- *       "additional_items": true
- *     }
- *   },
- *   "additional_items": {
- *     "variant": true
- *   },
- *   "return_order": {
- *     "items": true,
- *     "shipping_method": {
- *       "tax_lines": true
- *     }
- *   }
- * }
- * @param collection
- */
 function buildRelationsOrSelect(collection: string[]): Selects | Relations {
-  collection = collection.sort()
-  const output: Selects | Relations = {}
-
-  for (const relation of collection) {
-    if (relation.indexOf(".") > -1) {
-      const nestedRelations = relation.split(".")
-
-      let parent = output
-
-      while (nestedRelations.length > 1) {
-        const nestedRelation = nestedRelations.shift() as string
-        parent = parent[nestedRelation] = (
-          parent[nestedRelation] !== true &&
-          typeof parent[nestedRelation] === "object"
-            ? parent[nestedRelation]
-            : {}
-        ) as Selects | Relations
-      }
-
-      parent[nestedRelations[0]] = true
-
-      continue
-    }
-
-    output[relation] = output[relation] ?? true
-  }
-
-  return output
+  return objectFromStringPath(collection)
 }
 
 /**

packages/utils/src/common/index.ts

@@ -10,16 +10,16 @@ export * from "./is-email"
 export * from "./is-object"
 export * from "./is-string"
 export * from "./lower-case-first"
-export * from "./upper-case-first"
+export * from "./map-object-to"
 export * from "./medusa-container"
+export * from "./object-from-string-path"
 export * from "./object-to-string-path"
 export * from "./set-metadata"
 export * from "./simple-hash"
-export * from "./wrap-handler"
-export * from "./to-kebab-case"
-export * from "./to-camel-case"
 export * from "./stringify-circular"
+export * from "./to-camel-case"
 export * from "./to-kebab-case"
 export * from "./to-pascal-case"
+export * from "./upper-case-first"
 export * from "./wrap-handler"
-export * from "./map-object-to"
+

packages/utils/src/common/object-from-string-path.ts

@@ -0,0 +1,75 @@
+/**
+ * Convert a collection of dot string into a nested object
+ * @example
+ * input: [
+ *    order,
+ *    order.items,
+ *    order.swaps,
+ *    order.swaps.additional_items,
+ *    order.discounts,
+ *    order.discounts.rule,
+ *    order.claims,
+ *    order.claims.additional_items,
+ *    additional_items,
+ *    additional_items.variant,
+ *    return_order,
+ *    return_order.items,
+ *    return_order.shipping_method,
+ *    return_order.shipping_method.tax_lines
+ * ]
+ * output: {
+ *   "order": {
+ *     "items": true,
+ *     "swaps": {
+ *       "additional_items": true
+ *     },
+ *     "discounts": {
+ *       "rule": true
+ *     },
+ *     "claims": {
+ *       "additional_items": true
+ *     }
+ *   },
+ *   "additional_items": {
+ *     "variant": true
+ *   },
+ *   "return_order": {
+ *     "items": true,
+ *     "shipping_method": {
+ *       "tax_lines": true
+ *     }
+ *   }
+ * }
+ * @param collection
+ */
+export function objectFromStringPath(
+  collection: string[]
+): Record<string, any> {
+  collection = collection.sort()
+  const output: Record<string, any> = {}
+
+  for (const relation of collection) {
+    if (relation.indexOf(".") > -1) {
+      const nestedRelations = relation.split(".")
+
+      let parent = output
+
+      while (nestedRelations.length > 1) {
+        const nestedRelation = nestedRelations.shift() as string
+        parent = parent[nestedRelation] =
+          parent[nestedRelation] !== true &&
+          typeof parent[nestedRelation] === "object"
+            ? parent[nestedRelation]
+            : {}
+      }
+
+      parent[nestedRelations[0]] = true
+
+      continue
+    }
+
+    output[relation] = output[relation] ?? true
+  }
+
+  return output
+}

packages/utils/src/feature-flags/index.ts

@@ -1,7 +1,9 @@
 export * from "./analytics"
 export * from "./order-editing"
-export * from "./sales-channels"
 export * from "./product-categories"
 export * from "./publishable-api-keys"
+export * from "./sales-channels"
 export * from "./tax-inclusive-pricing"
 export * from "./utils"
+export * from "./workflows"
+

packages/utils/src/feature-flags/utils/__tests__/flag-router.spec.ts

@@ -0,0 +1,154 @@
+import { FlagRouter } from "../flag-router"
+
+const someFlag = {
+  key: "some_flag",
+  default_val: false,
+  env_key: "MEDUSA_FF_SOME_FLAG",
+  description: "[WIP] Enable some flag",
+}
+
+const workflows = {
+  key: "workflows",
+  default_val: {},
+  env_key: "MEDUSA_FF_WORKFLOWS",
+  description: "[WIP] Enable workflows",
+}
+
+describe("FlagRouter", function () {
+  it("should set a top-level flag", async function () {
+    const flagRouter = new FlagRouter({})
+
+    flagRouter.setFlag(someFlag.key, true)
+
+    expect(flagRouter.listFlags()).toEqual([
+      {
+        key: someFlag.key,
+        value: true,
+      },
+    ])
+  })
+
+  it("should set a nested flag", async function () {
+    const flagRouter = new FlagRouter({})
+
+    flagRouter.setFlag(workflows.key, { createCart: true })
+
+    expect(flagRouter.listFlags()).toEqual([
+      {
+        key: workflows.key,
+        value: {
+          createCart: true,
+        },
+      },
+    ])
+  })
+
+  it("should append to a nested flag", async function () {
+    const flagRouter = new FlagRouter({})
+
+    flagRouter.setFlag(workflows.key, { createCart: true })
+    flagRouter.setFlag(workflows.key, { addShippingMethod: true })
+
+    expect(flagRouter.listFlags()).toEqual([
+      {
+        key: workflows.key,
+        value: {
+          createCart: true,
+          addShippingMethod: true,
+        },
+      },
+    ])
+  })
+
+  it("should check if top-level flag is enabled", async function () {
+    const flagRouter = new FlagRouter({
+      [someFlag.key]: true,
+    })
+
+    const isEnabled = flagRouter.isFeatureEnabled(someFlag.key)
+
+    expect(isEnabled).toEqual(true)
+  })
+
+  it("should check if nested flag is enabled", async function () {
+    const flagRouter = new FlagRouter({
+      [workflows.key]: {
+        createCart: true,
+      },
+    })
+
+    const isEnabled = flagRouter.isFeatureEnabled({ workflows: "createCart" })
+
+    expect(isEnabled).toEqual(true)
+  })
+
+  it("should check if nested flag is enabled using top-level access", async function () {
+    const flagRouter = new FlagRouter({
+      [workflows.key]: {
+        createCart: true,
+      },
+    })
+
+    const isEnabled = flagRouter.isFeatureEnabled(workflows.key)
+
+    expect(isEnabled).toEqual(true)
+  })
+
+  it("should return true if top-level is enabled using nested-level access", async function () {
+    const flagRouter = new FlagRouter({
+      [workflows.key]: true,
+    })
+
+    const isEnabled = flagRouter.isFeatureEnabled({
+      [workflows.key]: "createCart",
+    })
+
+    expect(isEnabled).toEqual(true)
+  })
+
+  it("should return false if flag is disabled using top-level access", async function () {
+    const flagRouter = new FlagRouter({
+      [workflows.key]: false,
+    })
+
+    const isEnabled = flagRouter.isFeatureEnabled(workflows.key)
+
+    expect(isEnabled).toEqual(false)
+  })
+
+  it("should return false if nested flag is disabled", async function () {
+    const flagRouter = new FlagRouter({
+      [workflows.key]: {
+        createCart: false,
+      },
+    })
+
+    const isEnabled = flagRouter.isFeatureEnabled({ workflows: "createCart" })
+
+    expect(isEnabled).toEqual(false)
+  })
+
+  it("should initialize with both types of flags", async function () {
+    const flagRouter = new FlagRouter({
+      [workflows.key]: {
+        createCart: true,
+      },
+      [someFlag.key]: true,
+    })
+
+    const flags = flagRouter.listFlags()
+
+    expect(flags).toEqual([
+      {
+        key: workflows.key,
+        value: {
+          createCart: true,
+        },
+      },
+      {
+        key: someFlag.key,
+        value: true,
+      },
+    ])
+  })
+})

packages/utils/src/feature-flags/utils/flag-router.ts

@@ -1,17 +1,68 @@
 import { FeatureFlagTypes } from "@medusajs/types"
+import { isObject, isString } from "../../common"
 
 export class FlagRouter implements FeatureFlagTypes.IFlagRouter {
-  private readonly flags: Record<string, boolean> = {}
+  private readonly flags: Record<string, boolean | Record<string, boolean>> = {}
 
-  constructor(flags: Record<string, boolean>) {
+  constructor(flags: Record<string, boolean | Record<string, boolean>>) {
     this.flags = flags
   }
 
-  public isFeatureEnabled(key: string): boolean {
-    return !!this.flags[key]
+  /**
+   * Check if a feature flag is enabled.
+   * There are two ways of using this method:
+   * 1. `isFeatureEnabled("myFeatureFlag")`
+   * 2. `isFeatureEnabled({ myNestedFeatureFlag: "someNestedFlag" })`
+   * We use 1. for top-level feature flags and 2. for nested feature flags. Almost all flags are top-level.
+   * An example of a nested flag is workflows. To use it, you would do:
+   * `isFeatureEnabled({ workflows: Workflows.CreateCart })`
+   * @param flag - The flag to check
+   * @return {boolean} - Whether the flag is enabled or not
+   */
+  public isFeatureEnabled(flag: string | Record<string, string>): boolean {
+    if (isString(flag)) {
+      return !!this.flags[flag]
+    }
+
+    if (isObject(flag)) {
+      const [nestedFlag, value] = Object.entries(flag)[0]
+
+      if (typeof this.flags[nestedFlag] === "boolean") {
+        return this.flags[nestedFlag] as boolean
+      }
+
+      return !!this.flags[nestedFlag]?.[value]
+    }
+
+    throw Error("Flag must be a string or an object")
   }
 
-  public setFlag(key: string, value = true): void {
+  /**
+   * Sets a feature flag.
+   * Flags take two shapes:
+   * setFlag("myFeatureFlag", true)
+   * setFlag("myFeatureFlag", { nestedFlag: true })
+   * These shapes are used for top-level and nested flags respectively, as explained in isFeatureEnabled.
+   * @param key - The key of the flag to set.
+   * @param value - The value of the flag to set.
+   * @return {void} - void
+   */
+  public setFlag(
+    key: string,
+    value: boolean | { [key: string]: boolean }
+  ): void {
+    if (isObject(value)) {
+      const existing = this.flags[key]
+
+      if (!existing) {
+        this.flags[key] = value
+        return
+      }
+
+      this.flags[key] = { ...(this.flags[key] as object), ...value }
+      return
+    }
+
     this.flags[key] = value
   }
 

packages/utils/src/feature-flags/workflows.ts

@@ -0,0 +1,8 @@
+import { FeatureFlagTypes } from "@medusajs/types"
+
+export const WorkflowsFeatureFlag: FeatureFlagTypes.FlagSettings = {
+  key: "workflows",
+  default_val: false,
+  env_key: "MEDUSA_FF_WORKFLOWS",
+  description: "[WIP] Enable workflows",
+}