feat: Add interface types

lib/flagsmith/package.json

@@ -1,6 +1,6 @@
 {
   "name": "flagsmith",
-  "version": "9.0.5",
+  "version": "9.1.0",
   "description": "Feature flagging to support continuous development",
   "main": "./index.js",
   "module": "./index.mjs",

lib/react-native-flagsmith/package.json

@@ -1,6 +1,6 @@
 {
   "name": "react-native-flagsmith",
-  "version": "9.0.5",
+  "version": "9.1.0",
   "description": "Feature flagging to support continuous development",
   "main": "./index.js",
   "repository": {

react.d.ts

@@ -8,11 +8,25 @@ export declare type FlagsmithContextType<F extends string = string, T extends st
     serverState?: IState;
     children: React.ReactElement[] | React.ReactElement;
 };
-export declare const FlagsmithProvider: FC<FlagsmithContextType>;
-export declare function useFlags<F extends string, T extends string>(_flags: readonly F[], _traits?: readonly T[]): {
+type UseFlagsReturn<
+    F extends string | Record<string, any>,
+    T extends string
+> = F extends string
+    ? {
     [K in F]: IFlagsmithFeature;
 } & {
     [K in T]: IFlagsmithTrait;
+}
+    : {
+    [K in keyof F]: IFlagsmithFeature<F[K]>;
+} & {
+    [K in T]: IFlagsmithTrait;
 };
-export declare const useFlagsmith: () => IFlagsmith;
+export declare const FlagsmithProvider: FC<FlagsmithContextType>;
+export declare function useFlags<
+    F extends string | Record<string, any>,
+    T extends string = string
+>(_flags: readonly F[], _traits?: readonly T[]): UseFlagsReturn<F, T>;
+export declare const useFlagsmith: <F extends string | Record<string, any>,
+    T extends string = string>() => IFlagsmith<F, T>;
 export declare const useFlagsmithLoading: () => LoadingState | undefined;

react.tsx

@@ -126,11 +126,40 @@ export function useFlagsmithLoading() {
     return loadingState
 }
 
-export function useFlags<F extends string=string, T extends string=string>(_flags: readonly F[], _traits: readonly T[] = []): {
-    [K in F]: IFlagsmithFeature
+type UseFlagsReturn<
+    F extends string | Record<string, any>,
+    T extends string
+> = F extends string
+    ? {
+    [K in F]: IFlagsmithFeature;
 } & {
-    [K in T]: IFlagsmithTrait
-} {
+    [K in T]: IFlagsmithTrait;
+}
+    : {
+    [K in keyof F]: IFlagsmithFeature<F[K]>;
+} & {
+    [K in T]: IFlagsmithTrait;
+};
+
+/**
+ * Example usage:
+ *
+ * // A) Using string flags:
+ * useFlags<"featureOne"|"featureTwo">(["featureOne", "featureTwo"]);
+ *
+ * // B) Using an object for F - this can be generated by our CLI: https://github.com/Flagsmith/flagsmith-cli :
+ * interface MyFeatureInterface {
+ *   featureOne: string;
+ *   featureTwo: number;
+ * }
+ * useFlags<MyFeatureInterface>(["featureOne", "featureTwo"]);
+ */
+export function useFlags<
+    F extends string | Record<string, any>,
+    T extends string = string
+>(
+    _flags: readonly F[], _traits: readonly T[] = []
+){
     const firstRender = useRef(true)
     const flags = useConstant<string[]>(flagsAsArray(_flags))
     const traits = useConstant<string[]>(flagsAsArray(_traits))
@@ -173,15 +202,18 @@ export function useFlags<F extends string=string, T extends string=string>(_flag
         return res
     }, [renderRef])
 
-    return res
+    return res as UseFlagsReturn<F, T>
 }
 
-export function useFlagsmith<F extends string=string, T extends string=string>() {
+export function useFlagsmith<
+    F extends string | Record<string, any>,
+    T extends string = string
+>() {
     const context = useContext(FlagsmithContext)
 
     if (!context) {
         throw new Error('useFlagsmith must be used with in a FlagsmithProvider')
     }
 
-    return context as IFlagsmith<F, T>
+    return context as unknown as IFlagsmith<F, T>
 }

test/default-flags.test.ts

@@ -1,4 +1,3 @@
-// Sample test
 import { defaultState, defaultStateAlt, FLAGSMITH_KEY, getFlagsmith, getStateToCheck } from './test-constants';
 import { IFlags } from '../types';
 

test/functions.test.ts

@@ -1,4 +1,3 @@
-// Sample test
 import { getFlagsmith } from './test-constants';
 
 describe('Flagsmith.functions', () => {

test/init.test.ts

@@ -1,4 +1,3 @@
-// Sample test
 import { waitFor } from '@testing-library/react';
 import {defaultState, FLAGSMITH_KEY, getFlagsmith, getStateToCheck, identityState} from './test-constants';
 import { promises as fs } from 'fs';

test/react-types.test.tsx

@@ -0,0 +1,95 @@
+import React from 'react';
+import {render} from '@testing-library/react';
+import {FlagsmithProvider, useFlags, useFlagsmith} from '../lib/flagsmith/react';
+import {getFlagsmith,} from './test-constants';
+
+
+describe.only('FlagsmithProvider', () => {
+    it('should allow supplying interface generics to useFlagsmith', () => {
+        const FlagsmithPage = ()=> {
+            const typedFlagsmith = useFlagsmith<
+                {
+                    stringFlag: string
+                    numberFlag: number
+                    objectFlag: { first_name: string }
+                }
+            >()
+            //@ts-expect-error - feature not defined
+            typedFlagsmith.hasFeature("fail")
+            //@ts-expect-error - feature not defined
+            typedFlagsmith.getValue("fail")
+
+            typedFlagsmith.hasFeature("stringFlag")
+            typedFlagsmith.hasFeature("numberFlag")
+            typedFlagsmith.getValue("stringFlag")
+            typedFlagsmith.getValue("numberFlag")
+
+            //eslint-disable-next-line @typescript-eslint/no-unused-vars
+            const stringFlag: string|null = typedFlagsmith.getValue("stringFlag")
+            //eslint-disable-next-line @typescript-eslint/no-unused-vars
+            const numberFlag: number|null = typedFlagsmith.getValue("numberFlag")
+            //eslint-disable-next-line @typescript-eslint/no-unused-vars
+            const firstName: string | undefined = typedFlagsmith.getValue("objectFlag")?.first_name
+
+            // @ts-expect-error - invalid does not exist on type announcement
+            //eslint-disable-next-line @typescript-eslint/no-unused-vars
+            const invalidPointer: string | undefined = typedFlagsmith.getValue("objectFlag")?.invalid
+
+            // @ts-expect-error - feature should be a number
+            // eslint-disable-next-line @typescript-eslint/no-unused-vars
+            const incorrectNumberFlag: string = typedFlagsmith.getValue("numberFlag")
+
+            return <></>
+        }
+        const onChange = jest.fn();
+        const {flagsmith,initConfig, mockFetch} = getFlagsmith({onChange})
+        render(
+            <FlagsmithProvider flagsmith={flagsmith} options={initConfig}>
+                <FlagsmithPage/>
+            </FlagsmithProvider>
+        );
+    });
+    it('should allow supplying interface generics to useFlags', () => {
+        const FlagsmithPage = ()=> {
+            const typedFlagsmith = useFlags<
+                {
+                    stringFlag: string
+                    numberFlag: number
+                    objectFlag: { first_name: string }
+                }
+            >([])
+            //@ts-expect-error - feature not defined
+            typedFlagsmith.fail?.enabled
+            //@ts-expect-error - feature not defined
+            typedFlagsmith.fail?.value
+
+            typedFlagsmith.numberFlag
+            typedFlagsmith.stringFlag
+            typedFlagsmith.objectFlag
+
+            //eslint-disable-next-line @typescript-eslint/no-unused-vars
+            const stringFlag: string = typedFlagsmith.stringFlag?.value
+            //eslint-disable-next-line @typescript-eslint/no-unused-vars
+            const numberFlag: number = typedFlagsmith.numberFlag?.value
+            //eslint-disable-next-line @typescript-eslint/no-unused-vars
+            const firstName: string = typedFlagsmith.objectFlag?.value.first_name
+
+            // @ts-expect-error - invalid does not exist on type announcement
+            //eslint-disable-next-line @typescript-eslint/no-unused-vars
+            const invalidPointer: string = typedFlagsmith.objectFlag?.value.invalid
+
+            // @ts-expect-error - feature should be a number
+            // eslint-disable-next-line @typescript-eslint/no-unused-vars
+            const incorrectNumberFlag: string = typedFlagsmith.numberFlag?.value
+
+            return <></>
+        }
+        const onChange = jest.fn();
+        const {flagsmith,initConfig, mockFetch} = getFlagsmith({onChange})
+        render(
+            <FlagsmithProvider flagsmith={flagsmith} options={initConfig}>
+                <FlagsmithPage/>
+            </FlagsmithProvider>
+        );
+    });
+});

test/types.test.ts

@@ -0,0 +1,55 @@
+// Sample test
+import {getFlagsmith} from './test-constants';
+import {IFlagsmith} from '../types';
+
+describe('Flagsmith Types', () => {
+
+    // The following tests will fail to compile if any of the types fail / expect-error has no type issues
+    // Therefor all of the following ts-expect-errors and eslint-disable-lines are by design
+    test('should allow supplying string generics to a flagsmith instance', async () => {
+        const { flagsmith,  } = getFlagsmith({ });
+        const typedFlagsmith = flagsmith as IFlagsmith<"flag1"|"flag2">
+        //@ts-expect-error - feature not defined
+        typedFlagsmith.hasFeature("fail")
+        //@ts-expect-error - feature not defined
+        typedFlagsmith.getValue("fail")
+
+        typedFlagsmith.hasFeature("flag1")
+        typedFlagsmith.hasFeature("flag2")
+        typedFlagsmith.getValue("flag1")
+        typedFlagsmith.getValue("flag2")
+    });
+    test('should allow supplying interface generics to a flagsmith instance', async () => {
+        const { flagsmith,  } = getFlagsmith({ });
+        const typedFlagsmith = flagsmith as IFlagsmith<
+            {
+                stringFlag: string
+                numberFlag: number
+                objectFlag: { first_name: string }
+            }>
+        //@ts-expect-error - feature not defined
+        typedFlagsmith.hasFeature("fail")
+        //@ts-expect-error - feature not defined
+        typedFlagsmith.getValue("fail")
+
+        typedFlagsmith.hasFeature("stringFlag")
+        typedFlagsmith.hasFeature("numberFlag")
+        typedFlagsmith.getValue("stringFlag")
+        typedFlagsmith.getValue("numberFlag")
+
+        //eslint-disable-next-line @typescript-eslint/no-unused-vars
+        const stringFlag: string | null = typedFlagsmith.getValue("stringFlag")
+        //eslint-disable-next-line @typescript-eslint/no-unused-vars
+        const numberFlag: number | null = typedFlagsmith.getValue("numberFlag")
+        //eslint-disable-next-line @typescript-eslint/no-unused-vars
+        const firstName: string | undefined = typedFlagsmith.getValue("objectFlag")?.first_name
+
+        // @ts-expect-error - invalid does not exist on type announcement
+        //eslint-disable-next-line @typescript-eslint/no-unused-vars
+        const invalidPointer: string = typedFlagsmith.getValue("objectFlag")?.invalid
+
+        // @ts-expect-error - feature should be a number
+        // eslint-disable-next-line @typescript-eslint/no-unused-vars
+        const incorrectNumberFlag: string = typedFlagsmith.getValue("numberFlag")
+    });
+});

types.d.ts

@@ -8,10 +8,11 @@ export type DynatraceObject = {
     "shortString": Record<string, string>,
     "javaDouble": Record<string, number>,
 }
-export interface IFlagsmithFeature {
-    id?: number;
+
+export interface IFlagsmithFeature<Value = IFlagsmithValue> {
+    id: numbers
     enabled: boolean;
-    value?: IFlagsmithValue;
+    value: Value;
 }
 
 export declare type IFlagsmithTrait = IFlagsmithValue | TraitEvaluationContext;
@@ -132,8 +133,28 @@ export interface IFlagsmithResponse {
         };
     }[];
 }
-
-export interface IFlagsmith<F extends string = string, T extends string = string> {
+type FKey<F> = F extends string ? F : keyof F;
+type FValue<F, K extends FKey<F>> = F extends string
+    ? IFlagsmithValue
+    : F[K] | null;
+/**
+ * Example usage:
+ *
+ * // A) Using string flags:
+ * import flagsmith from 'flagsmith' as IFlagsmith<"featureOne"|"featureTwo">;
+ *
+ * // B) Using an object for F - this can be generated by our CLI: https://github.com/Flagsmith/flagsmith-cli :
+ * interface MyFeatureInterface {
+ *   featureOne: string;
+ *   featureTwo: number;
+ * }
+ * import flagsmith from 'flagsmith' as IFlagsmith<MyFeatureInterface>;
+ */
+export interface IFlagsmith<
+F extends string | Record<string, any> = string,
+T extends string = string
+>
+{
     /**
      * Initialise the sdk against a particular environment
      */
@@ -194,7 +215,7 @@ export interface IFlagsmith<F extends string = string, T extends string = string
      * @example
      * flagsmith.hasFeature("enabled_by_default_feature", { fallback: true })
      */
-    hasFeature: (key: F, optionsOrSkipAnalytics?: HasFeatureOptions) => boolean;
+    hasFeature: (key: FKey<F>, optionsOrSkipAnalytics?: HasFeatureOptions) => boolean;
 
     /**
      * Returns the value of a feature, or a fallback value.
@@ -212,8 +233,11 @@ export interface IFlagsmith<F extends string = string, T extends string = string
      * flagsmith.getValue("font_size") // "12px"
      * flagsmith.getValue("font_size", { json: true, fallback: "8px" }) // "8px"
      */
-    getValue<T = IFlagsmithValue>(key: F, options?: GetValueOptions<T>, skipAnalytics?: boolean): IFlagsmithValue<T>;
-
+    getValue<K extends FKey<F>>(
+        key: K,
+        options?: GetValueOptions<FValue<F, K>>,
+        skipAnalytics?: boolean
+    ): IFlagsmithValue<FValue<F, K>>;
     /**
      * Get the value of a particular trait for the identified user
      */