fix: catch init error in useFlagsmith (#351)

* Revert "fix: CORS errors due to header changes (#342)"

This reverts commit 5c89532.

* fix: surface-init-error-in-react-wrappers

* fix: added-unhandled-error-test

* fix: linter

Author: Zaimwa9

.prettierrc.json

@@ -2,8 +2,8 @@
   "proseWrap": "always",
   "singleQuote": true,
   "printWidth": 120,
-  "trailingComma": "all",
   "tabWidth": 4,
+  "semi": false,
   "overrides": [
     {
       "files": "*.md",

flagsmith-core.ts

@@ -829,6 +829,10 @@ const Flagsmith = class {
             options.headers['Flagsmith-Application-Version'] = this.applicationMetadata.version;
         }
 
+        if (SDK_VERSION) {
+            options.headers['Flagsmith-SDK-user-agent'] = `flagsmith-js-sdk/${SDK_VERSION}`
+        }
+
         if (headers) {
             Object.assign(options.headers, headers);
         }

react.tsx

@@ -1,41 +1,30 @@
-import React, {
-    createContext,
-    FC,
-    useCallback,
-    useContext,
-    useEffect,
-    useMemo,
-    useRef,
-    useState,
-} from 'react';
-import Emitter from './utils/emitter';
-const events = new Emitter();
+import React, { createContext, FC, useCallback, useContext, useEffect, useMemo, useRef, useState } from 'react'
+import Emitter from './utils/emitter'
+const events = new Emitter()
 
 import { IFlagsmith, IFlagsmithTrait, IFlagsmithFeature, IState } from './types'
 
-export const FlagsmithContext = createContext<IFlagsmith<string,string> | null>(null)
+export const FlagsmithContext = createContext<IFlagsmith<string, string> | null>(null)
 export type FlagsmithContextType = {
     flagsmith: IFlagsmith // The flagsmith instance
     options?: Parameters<IFlagsmith['init']>[0] // Initialisation options, if you do not provide this you will have to call init manually
     serverState?: IState
-    children: React.ReactNode;
+    children: React.ReactNode
 }
 
-export const FlagsmithProvider: FC<FlagsmithContextType> = ({
-  flagsmith, options, serverState, children,
-                                                            }) => {
+export const FlagsmithProvider: FC<FlagsmithContextType> = ({ flagsmith, options, serverState, children }) => {
     const firstRenderRef = useRef(true)
     if (flagsmith && !flagsmith?._trigger) {
         flagsmith._trigger = () => {
             // @ts-expect-error using internal function, consumers would never call this
-            flagsmith.log("React - trigger event received")
-            events.emit('event');
+            flagsmith?.log('React - trigger event received')
+            events.emit('event')
         }
     }
 
     if (flagsmith && !flagsmith?._triggerLoadingState) {
         flagsmith._triggerLoadingState = () => {
-            events.emit('loading_event');
+            events.emit('loading_event')
         }
     }
 
@@ -46,22 +35,24 @@ export const FlagsmithProvider: FC<FlagsmithContextType> = ({
     if (firstRenderRef.current) {
         firstRenderRef.current = false
         if (options) {
-            flagsmith.init({
-                ...options,
-                state: options.state || serverState,
-                onChange: (...args) => {
-                    if (options.onChange) {
-                        options.onChange(...args)
-                    }
-                },
-            })
+            flagsmith
+                .init({
+                    ...options,
+                    state: options.state || serverState,
+                    onChange: (...args) => {
+                        if (options.onChange) {
+                            options.onChange(...args)
+                        }
+                    },
+                })
+                .catch((error) => {
+                    // @ts-expect-error using internal function, consumers would never call this
+                    flagsmith?.log('React - Failed to initialize flagsmith', error)
+                    events.emit('event')
+                })
         }
     }
-    return (
-        <FlagsmithContext.Provider value={flagsmith}>
-            {children}
-        </FlagsmithContext.Provider>
-    )
+    return <FlagsmithContext.Provider value={flagsmith}>{children}</FlagsmithContext.Provider>
 }
 
 const useConstant = function <T>(value: T): T {
@@ -72,7 +63,6 @@ const useConstant = function <T>(value: T): T {
     return ref.current
 }
 
-
 const flagsAsArray = (_flags: any): string[] => {
     if (typeof _flags === 'string') {
         return [_flags]
@@ -82,29 +72,26 @@ const flagsAsArray = (_flags: any): string[] => {
             return _flags
         }
     }
-    throw new Error(
-        'Flagsmith: please supply an array of strings or a single string of flag keys to useFlags',
-    )
+    throw new Error('Flagsmith: please supply an array of strings or a single string of flag keys to useFlags')
 }
 
 const getRenderKey = (flagsmith: IFlagsmith, flags: string[], traits: string[] = []) => {
     return flags
         .map((k) => {
             return `${flagsmith.getValue(k)}${flagsmith.hasFeature(k)}`
-        }).concat(traits.map((t) => (
-            `${flagsmith.getTrait(t)}`
-        )))
+        })
+        .concat(traits.map((t) => `${flagsmith.getTrait(t)}`))
         .join(',')
 }
 
 export function useFlagsmithLoading() {
-    const flagsmith = useContext(FlagsmithContext);
-    const [loadingState, setLoadingState] = useState(flagsmith?.loadingState);
-    const [subscribed, setSubscribed] = useState(false);
+    const flagsmith = useContext(FlagsmithContext)
+    const [loadingState, setLoadingState] = useState(flagsmith?.loadingState)
+    const [subscribed, setSubscribed] = useState(false)
     const refSubscribed = useRef(subscribed)
 
     const eventListener = useCallback(() => {
-        setLoadingState(flagsmith?.loadingState);
+        setLoadingState(flagsmith?.loadingState)
     }, [flagsmith])
     if (!refSubscribed.current) {
         events.on('loading_event', eventListener)
@@ -120,26 +107,23 @@ export function useFlagsmithLoading() {
             if (subscribed) {
                 events.off('loading_event', eventListener)
             }
-        };
+        }
     }, [flagsmith, subscribed, eventListener])
 
     return loadingState
 }
 
-type UseFlagsReturn<
-    F extends string | Record<string, any>,
-    T extends string
-> = [F] extends [string]
+type UseFlagsReturn<F extends string | Record<string, any>, T extends string> = F extends string
     ? {
-    [K in F]: IFlagsmithFeature;
-} & {
-    [K in T]: IFlagsmithTrait;
-}
+          [K in F]: IFlagsmithFeature
+      } & {
+          [K in T]: IFlagsmithTrait
+      }
     : {
-    [K in keyof F]: IFlagsmithFeature<F[K]>;
-} & {
-    [K in T]: IFlagsmithTrait;
-};
+          [K in keyof F]: IFlagsmithFeature<F[K]>
+      } & {
+          [K in T]: IFlagsmithTrait
+      }
 
 /**
  * Example usage:
@@ -154,61 +138,58 @@ type UseFlagsReturn<
  * }
  * useFlags<MyFeatureInterface>(["featureOne", "featureTwo"]);
  */
-export function useFlags<
-    F extends string | Record<string, any>,
-    T extends string = string
->(
-    _flags: readonly (F | keyof F)[], _traits: readonly T[] = []
-){
+export function useFlags<F extends string | Record<string, any>, T extends string = string>(
+    _flags: readonly (F | keyof F)[],
+    _traits: readonly T[] = []
+) {
     const firstRender = useRef(true)
     const flags = useConstant<string[]>(flagsAsArray(_flags))
     const traits = useConstant<string[]>(flagsAsArray(_traits))
     const flagsmith = useContext(FlagsmithContext)
-    const [renderRef, setRenderRef] = useState(getRenderKey(flagsmith as IFlagsmith, flags, traits));
+    const [renderRef, setRenderRef] = useState(getRenderKey(flagsmith as IFlagsmith, flags, traits))
     const eventListener = useCallback(() => {
         const newRenderKey = getRenderKey(flagsmith as IFlagsmith, flags, traits)
         if (newRenderKey !== renderRef) {
             // @ts-expect-error using internal function, consumers would never call this
-            flagsmith?.log("React - useFlags flags and traits have changed")
+            flagsmith?.log('React - useFlags flags and traits have changed')
             setRenderRef(newRenderKey)
         }
     }, [renderRef])
-    const emitterRef = useRef(events.once('event', eventListener));
-
-
+    const emitterRef = useRef(events.once('event', eventListener))
 
     if (firstRender.current) {
-        firstRender.current = false;
+        firstRender.current = false
         // @ts-expect-error using internal function, consumers would never call this
-        flagsmith?.log("React - Initialising event listeners")
+        flagsmith?.log('React - Initialising event listeners')
     }
 
-    useEffect(()=>{
+    useEffect(() => {
         return () => {
             emitterRef.current?.()
         }
     }, [])
 
     const res = useMemo(() => {
         const res: any = {}
-    flags.map((k) => {
+        flags
+            .map((k) => {
                 res[k] = {
                     enabled: flagsmith!.hasFeature(k),
                     value: flagsmith!.getValue(k),
                 }
-    }).concat(traits?.map((v) => {
+            })
+            .concat(
+                traits?.map((v) => {
                     res[v] = flagsmith!.getTrait(v)
-    }))
+                })
+            )
         return res
     }, [renderRef])
 
     return res as UseFlagsReturn<F, T>
 }
 
-export function useFlagsmith<
-    F extends string | Record<string, any>,
-    T extends string = string
->() {
+export function useFlagsmith<F extends string | Record<string, any>, T extends string = string>() {
     const context = useContext(FlagsmithContext)
 
     if (!context) {

test/init.test.ts

@@ -292,6 +292,7 @@ describe('Flagsmith.init', () => {
                 headers: expect.objectContaining({
                     'Flagsmith-Application-Name': 'Test App',
                     'Flagsmith-Application-Version': '1.2.3',
+                    'Flagsmith-SDK-user-agent': `flagsmith-js-sdk/${SDK_VERSION}`,
                 }),
             }),
         );