Feat node server side

.github/workflows/tests.yaml

@@ -11,14 +11,12 @@ on:
 jobs:
   build:
     runs-on: ubuntu-latest
-
     steps:
       - uses: actions/checkout@v3
       - name: Use Node.js
         uses: actions/setup-node@v3
         with:
           node-version: "16.19.0"
-
       - uses: pnpm/action-setup@v2
         name: Install pnpm
         id: pnpm-install

.vscode/settings.json

@@ -6,6 +6,9 @@
   "[typescript][typescriptreact][typescriptangular]": {
     "editor.defaultFormatter": "esbenp.prettier-vscode"
   },
-  "eslint.workingDirectories": ["apps", "packages"],
+  "eslint.workingDirectories": [
+    "apps",
+    "packages"
+  ],
   "prettier.enable": true
-}
+}

packages/core/src/index.ts

@@ -20,7 +20,7 @@ export type ABConfig<T extends string = string> = {
 
 type Settings<
   FlagName extends string,
-  Flags extends Record<FlagName, FlagValueString> = Record<FlagName, FlagValueString>
+  Flags extends Record<FlagName, FlagValueString> = Record<FlagName, FlagValueString>,
 > = {
   flags?: {
     defaultValues?: {
@@ -44,14 +44,19 @@ type LocalData<FlagName extends string = string, TestName extends string = strin
 };
 
 interface PersistentStorage {
-  get: (key: string) => string | null;
-  set: (key: string, value: string) => void;
+  get: (key: string, args?: unknown) => string | null;
+  set: (key: string, value: string, args?: unknown) => void;
 }
 
+type flagCacheConfig = {
+  refetchFlags: boolean;
+  timeToLive: number;
+};
+
 export type AbbyConfig<
   FlagName extends string = string,
   Tests extends Record<string, ABConfig> = Record<string, ABConfig>,
-  Flags extends Record<FlagName, FlagValueString> = Record<FlagName, FlagValueString>
+  Flags extends Record<FlagName, FlagValueString> = Record<FlagName, FlagValueString>,
 > = {
   projectId: string;
   apiUrl?: string;
@@ -60,17 +65,25 @@ export type AbbyConfig<
   flags?: Flags;
   settings?: Settings<F.NoInfer<FlagName>, Flags>;
   debug?: boolean;
+  flagCacheConfig?: flagCacheConfig;
 };
 
 export class Abby<
   FlagName extends string,
   TestName extends string,
   Tests extends Record<string, ABConfig>,
-  Flags extends Record<FlagName, FlagValueString>
+  Flags extends Record<FlagName, FlagValueString>,
 > {
   private log = (...args: any[]) =>
     this.config.debug ? console.log(`core.Abby`, ...args) : () => {};
 
+  private testDevtoolOverrides: Map<keyof Tests, Tests[keyof Tests]["variants"][number]> =
+    new Map();
+
+  private flagDevtoolOverrides: Map<FlagName, boolean> = new Map();
+
+  #flagTimeoutMap: Map<string, Date> = new Map();
+
   #data: LocalData<FlagName, TestName> = {
     tests: {} as any,
     flags: {} as any,
@@ -92,13 +105,16 @@ export class Abby<
     private persistantFlagStorage?: PersistentStorage
   ) {
     this._cfg = config as AbbyConfig<FlagName, Tests, Flags>;
-    this.#data.flags = Object.keys(config.flags ?? {}).reduce((acc, flagName) => {
-      acc[flagName as FlagName] = this.getDefaultFlagValue(
-        flagName as FlagName,
-        config.flags as any
-      );
-      return acc;
-    }, {} as Record<FlagName, FlagValue>);
+    this.#data.flags = Object.keys(config.flags ?? {}).reduce(
+      (acc, flagName) => {
+        acc[flagName as FlagName] = this.getDefaultFlagValue(
+          flagName as FlagName,
+          config.flags as any
+        );
+        return acc;
+      },
+      {} as Record<FlagName, FlagValue>
+    );
     this.#data.tests = config.tests ?? ({} as any);
   }
 
@@ -139,22 +155,32 @@ export class Abby<
     data: AbbyDataResponse
   ): LocalData<FlagName, TestName> {
     return {
-      tests: data.tests.reduce((acc, { name, weights }) => {
-        if (!acc[name as keyof Tests]) {
+      tests: data.tests.reduce(
+        (acc, { name, weights }) => {
+          if (!acc[name as keyof Tests]) {
+            return acc;
+          }
+
+          // assigned the fetched weights to the initial config
+          acc[name as keyof Tests] = {
+            ...acc[name as keyof Tests],
+            weights,
+          };
           return acc;
-        }
-
-        // assigned the fetched weights to the initial config
-        acc[name as keyof Tests] = {
-          ...acc[name as keyof Tests],
-          weights,
-        };
-        return acc;
-      }, (this.config.tests ?? {}) as any),
-      flags: data.flags.reduce((acc, { name, value }) => {
-        acc[name] = value;
-        return acc;
-      }, {} as Record<string, FlagValue>),
+        },
+        (this.config.tests ?? {}) as any
+      ),
+      flags: data.flags.reduce(
+        (acc, { name, value }) => {
+          const validUntil = new Date(
+            new Date().getTime() + 1000 * 60 * (this.config.flagCacheConfig?.timeToLive ?? 1)
+          ); // flagdefault timeout is 1 minute
+          this.#flagTimeoutMap.set(name, validUntil);
+          acc[name] = value;
+          return acc;
+        },
+        {} as Record<string, FlagValue>
+      ),
     };
   }
 
@@ -201,6 +227,37 @@ export class Abby<
     return this.getProjectData();
   }
 
+  /**
+   * Helper function to retrieve the time a flag is valid
+   * @param key
+   * @returns
+   */
+  getFeatureFlagTimeout<F extends FlagName>(key: F) {
+    return this.#flagTimeoutMap.get(key);
+  }
+
+  /**
+   * Helper function to check if a featureflag should be refetched
+   * @param key name of the featureflag
+   * @returns value of flag
+   */
+  getValidFlag<F extends FlagName>(key: F) {
+    const flagTime = this.#flagTimeoutMap.get(key);
+    if (!flagTime) return this.#data.flags[key];
+    const now = new Date();
+    if (flagTime.getTime() <= now.getTime()) {
+      this.refetchFlags();
+    }
+    return this.#data.flags[key];
+  }
+
+  /**
+   * helper function to make testing easier
+   */
+  refetchFlags() {
+    this.loadProjectData();
+  }
+
   /**
    * Function to get the value of a feature flag. This includes
    * the overrides from the dev tools and the local overrides if in development mode
@@ -213,7 +270,9 @@ export class Abby<
   ): FlagValueStringToType<CurrentFlag> {
     this.log(`getFeatureFlag()`, key);
 
-    const storedValue = this.#data.flags[key as unknown as FlagName];
+    const storedValue = this.config.flagCacheConfig?.refetchFlags
+      ? this.getValidFlag(key as unknown as FlagName)
+      : this.#data.flags[key as unknown as FlagName];
 
     const localOverride = this.flagOverrides?.get(key as unknown as FlagName);
 
@@ -254,7 +313,10 @@ export class Abby<
    * @param key The name of the test
    * @returns the value of the test variant
    */
-  getTestVariant<T extends keyof Tests>(key: T): Tests[T]["variants"][number] {
+  getTestVariant<T extends keyof Tests, T_ARGS = unknown>(
+    key: T,
+    args?: T_ARGS
+  ): Tests[T]["variants"][number] {
     this.log(`getTestVariant()`, key);
 
     const { variants, weights } = (this.#data.tests as LocalData["tests"])[
@@ -267,7 +329,7 @@ export class Abby<
       return override;
     }
 
-    const persistedValue = this.persistantTestStorage?.get(key as string);
+    const persistedValue = this.persistantTestStorage?.get(key as string, args);
 
     if (persistedValue != null) {
       this.log(`getTestVariant() => persistedValue:`, persistedValue);
@@ -276,7 +338,7 @@ export class Abby<
     }
 
     const weightedVariant = getWeightedRandomVariant(variants, weights);
-    this.persistantTestStorage?.set(key as string, weightedVariant);
+    this.persistantTestStorage?.set(key as string, weightedVariant, args);
 
     this.log(`getTestVariant() => weightedVariant:`, weightedVariant);
 

packages/core/src/shared/helpers.ts

@@ -9,5 +9,5 @@ export function getFFStorageKey(projectId: string, flagName: string): string {
 }
 
 export function assertUnreachable(x: never): never {
-  throw new Error("Reached unreachable code");
+  throw new Error(`Reached unreachable code: ${x}`);
 }

packages/core/src/shared/http.ts

@@ -1,5 +1,6 @@
 import { ABBY_BASE_URL } from "./constants";
 import type { AbbyEventType, AbbyEvent, AbbyDataResponse } from "./index";
+
 export abstract class HttpService {
   static async getProjectData({
     projectId,
@@ -21,6 +22,7 @@ export abstract class HttpService {
       const data = (await res.json()) as AbbyDataResponse;
       return data;
     } catch (err) {
+      console.log(err);
       console.error("[ABBY]: failed to load project data, falling back to defaults");
       return null;
     }