feat: extract flag evaluation engine into @flaggly/engine package

src/__tests__/engine.spec.ts → engine/__tests__/engine.spec.ts

@@ -3,8 +3,8 @@ import {
 	evaluateFlag,
 	evaluateRolloutStep,
 	evaluateRolloutSteps,
-} from "../engine";
-import type { FeatureFlagInputSchema, FlagEvaluationInput } from "../schema";
+} from "../engine.ts";
+import type { FeatureFlagInputSchema, FlagEvaluationInput } from "../types.ts";
 
 function createMockInput(
 	overrides?: Partial<FlagEvaluationInput>,

src/__tests__/example.spec.ts → engine/__tests__/example.spec.ts

@@ -1,6 +1,6 @@
 import { describe, expect, test } from "vitest";
-import { evaluateFlag } from "../engine";
-import type { FlagEvaluationInput } from "../schema";
+import { evaluateFlag } from "../engine.ts";
+import type { FlagEvaluationInput } from "../types.ts";
 
 /**
  * Helper to create properly structured evaluation input

src/engine.ts → engine/engine.ts

@@ -3,7 +3,7 @@ import type {
 	FeatureFlagInputSchema,
 	FlagEvaluationInput,
 	FlagResultSchema,
-} from "./schema";
+} from "./types";
 
 jexl.addTransform("split", (val, char) => val.split(char));
 jexl.addTransform("lower", (val) => val.toLowerCase());

engine/index.ts

@@ -0,0 +1,2 @@
+export * from "./engine";
+export * from "./types";

engine/package.json

@@ -0,0 +1,34 @@
+{
+	"name": "@flaggly/engine",
+	"version": "0.2.0",
+	"description": "Flaggly feature flag evaluation engine",
+	"main": "dist/index.js",
+	"module": "dist/index.mjs",
+	"types": "dist/index.d.ts",
+	"files": [
+		"dist",
+		"README.md"
+	],
+	"keywords": [
+		"feature-flags",
+		"engine",
+		"typescript",
+		"cloudflare"
+	],
+	"author": "butttons",
+	"license": "MIT",
+	"dependencies": {
+		"jexl": "^2.3.0"
+	},
+	"repository": {
+		"type": "git",
+		"url": "https://github.com/butttons/flaggly"
+	},
+	"exports": {
+		".": {
+			"types": "./dist/index.d.ts",
+			"import": "./dist/index.mjs",
+			"require": "./dist/index.js"
+		}
+	}
+}

engine/tsconfig.engine.json

@@ -0,0 +1,20 @@
+{
+	"compilerOptions": {
+		"target": "ES2022",
+		"module": "ESNext",
+		"moduleResolution": "Bundler",
+		"declaration": true,
+		"declarationMap": true,
+		"emitDeclarationOnly": false,
+		"outDir": "../../dist/engine",
+		"rootDir": "../",
+		"strict": true,
+		"strictNullChecks": false,
+		"esModuleInterop": true,
+		"forceConsistentCasingInFileNames": true,
+		"skipLibCheck": true,
+		"types": []
+	},
+	"include": ["./**/*.ts"],
+	"exclude": ["**/*.test.ts", "**/*.spec.ts", "node_modules"]
+}

engine/types.ts

@@ -0,0 +1,98 @@
+export type RolloutStep = {
+	start: string;
+	percentage?: number;
+	segment?: string;
+};
+
+export type FeatureFlagVariation = {
+	id: string;
+	label?: string;
+	weight: number;
+	payload?: unknown;
+};
+
+export type FeatureFlagInputSchema =
+	| {
+			id: string;
+			label?: string;
+			description?: string;
+			enabled: boolean;
+			type: "boolean";
+			rules: string[];
+			segments: string[];
+			rollout: number;
+			rollouts: RolloutStep[];
+			isTrackable: boolean;
+		}
+	| {
+			id: string;
+			label?: string;
+			description?: string;
+			enabled: boolean;
+			type: "payload";
+			payload: unknown;
+			rules: string[];
+			segments: string[];
+			rollout: number;
+			rollouts: RolloutStep[];
+			isTrackable: boolean;
+		}
+	| {
+			id: string;
+			label?: string;
+			description?: string;
+			enabled: boolean;
+			type: "variant";
+			variations: FeatureFlagVariation[];
+			rules: string[];
+			segments: string[];
+			rollout: number;
+			rollouts: RolloutStep[];
+			isTrackable: boolean;
+		};
+
+export type FlagEvaluationInput = {
+	user?: unknown;
+	id?: string;
+	request: {
+		headers: Record<string, string>;
+	};
+	page: {
+		url?: string | null;
+	};
+	geo: {
+		country?: string;
+		isEUCountry?: boolean;
+		continent?: string;
+		city?: string;
+		postalCode?: string;
+		latitude?: string;
+		longitude?: string;
+		timezone?: string;
+		region?: string;
+		regionCode?: string;
+		metroCode?: string;
+	};
+};
+
+export type FlagResultSchema =
+	| {
+			type: "boolean";
+			result: boolean;
+			isEval: boolean;
+		}
+	| {
+			type: "payload";
+			result: unknown;
+			isEval: boolean;
+		}
+	| {
+			type: "variant";
+			result: unknown;
+			isEval: boolean;
+		};
+
+export type AppData = {
+	flags: Record<string, FeatureFlagInputSchema>;
+	segments: Record<string, string>;
+};

package.json

@@ -11,12 +11,14 @@
     "test": "vitest",
     "test:run": "vitest run",
     "build:sdk": "tsup sdk/index.ts --dts --format esm,cjs --tsconfig sdk/tsconfig.sdk.json --out-dir sdk/dist",
-    "sandbox:sdk": "tsx sdk/sandbox.ts"
+    "sandbox:sdk": "tsx sdk/sandbox.ts",
+    "build:engine": "tsup engine/index.ts --dts --format esm,cjs --tsconfig engine/tsconfig.engine.json --out-dir engine/dist"
   },
   "dependencies": {
     "hono": "^4.9.9",
     "jexl": "^2.3.0",
-    "zod": "^4.1.11"
+    "zod": "^4.1.11",
+    "@flaggly/engine": "workspace:*"
   },
   "devDependencies": {
     "@types/jexl": "^2.3.4",