chore: Refactor SDK structure (#473)

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## This PR
Splits up the types file and restructures the SDK by functionalities.
Feeling quite good with the structure now.
The PR became quite huge, but I could even move one or two more things
(for the client) to the shared implementation.
@toddbaert @beeme1mr Please give feedback if you think the structure is
completely off or something seems odd to you🙂

### Related Issues
<!-- add here the GitHub issue that this PR resolves if applicable -->

Fixes #437

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

Author: lukas-reining

Diff for: packages/client/src/client/client.ts

@@ -0,0 +1,6 @@
+import { ClientMetadata, EvaluationLifeCycle, Eventing, ManageLogger } from '@openfeature/shared';
+import { Features } from '../evaluation';
+
+export interface Client extends EvaluationLifeCycle<Client>, Features, ManageLogger<Client>, Eventing {
+  readonly metadata: ClientMetadata;
+}

Diff for: packages/client/src/client/index.ts

@@ -0,0 +1,2 @@
+export * from './client';
+export * from './open-feature-client';

Diff for: packages/client/src/client.ts renamed to packages/client/src/client/open-feature-client.ts

@@ -1,3 +1,5 @@
+import { Client } from './client';
+import { Provider } from '../provider';
 import {
   ClientMetadata,
   ErrorCode,
@@ -6,6 +8,7 @@ import {
   EventHandler,
   FlagValue,
   FlagValueType,
+  Hook,
   HookContext,
   JsonValue,
   Logger,
@@ -17,8 +20,8 @@ import {
   SafeLogger,
   StandardResolutionReasons,
 } from '@openfeature/shared';
-import { OpenFeature } from './open-feature';
-import { Client, FlagEvaluationOptions, Hook, Provider } from './types';
+import { OpenFeature } from '../open-feature';
+import { FlagEvaluationOptions } from '../evaluation';
 
 type OpenFeatureClientOptions = {
   name?: string;

Diff for: packages/client/src/evaluation/evaluation.ts

@@ -0,0 +1,118 @@
+import { EvaluationDetails, Hook, HookHints, JsonValue } from '@openfeature/shared';
+
+export interface FlagEvaluationOptions {
+  hooks?: Hook[];
+  hookHints?: HookHints;
+}
+
+export interface Features {
+  /**
+   * Performs a flag evaluation that returns a boolean.
+   * @param {string} flagKey The flag key uniquely identifies a particular flag
+   * @param {boolean} defaultValue The value returned if an error occurs
+   * @param {FlagEvaluationOptions} options Additional flag evaluation options
+   * @returns {boolean} Flag evaluation response
+   */
+  getBooleanValue(flagKey: string, defaultValue: boolean, options?: FlagEvaluationOptions): boolean;
+
+  /**
+   * Performs a flag evaluation that a returns an evaluation details object.
+   * @param {string} flagKey The flag key uniquely identifies a particular flag
+   * @param {boolean} defaultValue The value returned if an error occurs
+   * @param {FlagEvaluationOptions} options Additional flag evaluation options
+   * @returns {EvaluationDetails<boolean>} Flag evaluation details response
+   */
+  getBooleanDetails(
+    flagKey: string,
+    defaultValue: boolean,
+    options?: FlagEvaluationOptions
+  ): EvaluationDetails<boolean>;
+
+  /**
+   * Performs a flag evaluation that returns a string.
+   * @param {string} flagKey The flag key uniquely identifies a particular flag
+   * @template {string} T A optional generic argument constraining the string
+   * @param {T} defaultValue The value returned if an error occurs
+   * @param {FlagEvaluationOptions} options Additional flag evaluation options
+   * @returns {T} Flag evaluation response
+   */
+  getStringValue(flagKey: string, defaultValue: string, options?: FlagEvaluationOptions): string;
+
+  getStringValue<T extends string = string>(flagKey: string, defaultValue: T, options?: FlagEvaluationOptions): T;
+
+  /**
+   * Performs a flag evaluation that a returns an evaluation details object.
+   * @param {string} flagKey The flag key uniquely identifies a particular flag
+   * @template {string} T A optional generic argument constraining the string
+   * @param {T} defaultValue The value returned if an error occurs
+   * @param {FlagEvaluationOptions} options Additional flag evaluation options
+   * @returns {EvaluationDetails<T>} Flag evaluation details response
+   */
+  getStringDetails(flagKey: string, defaultValue: string, options?: FlagEvaluationOptions): EvaluationDetails<string>;
+
+  getStringDetails<T extends string = string>(
+    flagKey: string,
+    defaultValue: T,
+    options?: FlagEvaluationOptions
+  ): EvaluationDetails<T>;
+
+  /**
+   * Performs a flag evaluation that returns a number.
+   * @param {string} flagKey The flag key uniquely identifies a particular flag
+   * @template {number} T A optional generic argument constraining the number
+   * @param {T} defaultValue The value returned if an error occurs
+   * @param {FlagEvaluationOptions} options Additional flag evaluation options
+   * @returns {T} Flag evaluation response
+   */
+  getNumberValue(flagKey: string, defaultValue: number, options?: FlagEvaluationOptions): number;
+
+  getNumberValue<T extends number = number>(flagKey: string, defaultValue: T, options?: FlagEvaluationOptions): T;
+
+  /**
+   * Performs a flag evaluation that a returns an evaluation details object.
+   * @param {string} flagKey The flag key uniquely identifies a particular flag
+   * @template {number} T A optional generic argument constraining the number
+   * @param {T} defaultValue The value returned if an error occurs
+   * @param {FlagEvaluationOptions} options Additional flag evaluation options
+   * @returns {Promise<EvaluationDetails<T>>} Flag evaluation details response
+   */
+  getNumberDetails(flagKey: string, defaultValue: number, options?: FlagEvaluationOptions): EvaluationDetails<number>;
+
+  getNumberDetails<T extends number = number>(
+    flagKey: string,
+    defaultValue: T,
+    options?: FlagEvaluationOptions
+  ): EvaluationDetails<T>;
+
+  /**
+   * Performs a flag evaluation that returns an object.
+   * @param {string} flagKey The flag key uniquely identifies a particular flag
+   * @template {JsonValue} T A optional generic argument describing the structure
+   * @param {T} defaultValue The value returned if an error occurs
+   * @param {FlagEvaluationOptions} options Additional flag evaluation options
+   * @returns {Promise<T>} Flag evaluation response
+   */
+  getObjectValue(flagKey: string, defaultValue: JsonValue, options?: FlagEvaluationOptions): JsonValue;
+
+  getObjectValue<T extends JsonValue = JsonValue>(flagKey: string, defaultValue: T, options?: FlagEvaluationOptions): T;
+
+  /**
+   * Performs a flag evaluation that a returns an evaluation details object.
+   * @param {string} flagKey The flag key uniquely identifies a particular flag
+   * @template {JsonValue} T A optional generic argument describing the structure
+   * @param {T} defaultValue The value returned if an error occurs
+   * @param {FlagEvaluationOptions} options Additional flag evaluation options
+   * @returns {Promise<EvaluationDetails<T>>} Flag evaluation details response
+   */
+  getObjectDetails(
+    flagKey: string,
+    defaultValue: JsonValue,
+    options?: FlagEvaluationOptions
+  ): EvaluationDetails<JsonValue>;
+
+  getObjectDetails<T extends JsonValue = JsonValue>(
+    flagKey: string,
+    defaultValue: T,
+    options?: FlagEvaluationOptions
+  ): EvaluationDetails<T>;
+}

Diff for: packages/client/src/evaluation/index.ts

@@ -0,0 +1 @@
+export * from './evaluation';

Diff for: packages/client/src/index.ts

@@ -1,5 +1,5 @@
 export * from './client';
-export * from './no-op-provider';
+export * from './provider';
+export * from './evaluation';
 export * from './open-feature';
-export * from './types';
-export * from '@openfeature/shared';
+export * from '@openfeature/shared';

Diff for: packages/client/src/open-feature.ts

@@ -1,7 +1,6 @@
-import { EvaluationContext, FlagValue, Logger, OpenFeatureCommonAPI, SafeLogger } from '@openfeature/shared';
-import { OpenFeatureClient } from './client';
-import { NOOP_PROVIDER } from './no-op-provider';
-import { Client, Hook, Provider } from './types';
+import { EvaluationContext, ManageContext, OpenFeatureCommonAPI } from '@openfeature/shared';
+import { Client, OpenFeatureClient } from './client';
+import { NOOP_PROVIDER, Provider } from './provider';
 
 // use a symbol as a key for the global singleton
 const GLOBAL_OPENFEATURE_API_KEY = Symbol.for('@openfeature/web-sdk/api');
@@ -11,8 +10,7 @@ type OpenFeatureGlobal = {
 };
 const _globalThis = globalThis as OpenFeatureGlobal;
 
-export class OpenFeatureAPI extends OpenFeatureCommonAPI<Provider> {
-  protected _hooks: Hook[] = [];
+export class OpenFeatureAPI extends OpenFeatureCommonAPI<Provider> implements ManageContext<Promise<void>> {
   protected _defaultProvider: Provider = NOOP_PROVIDER;
 
   // eslint-disable-next-line @typescript-eslint/no-empty-function
@@ -36,31 +34,16 @@ export class OpenFeatureAPI extends OpenFeatureCommonAPI<Provider> {
     return instance;
   }
 
-  setLogger(logger: Logger): this {
-    this._logger = new SafeLogger(logger);
-    return this;
-  }
-
-  addHooks(...hooks: Hook<FlagValue>[]): this {
-    this._hooks = [...this._hooks, ...hooks];
-    return this;
-  }
-
-  getHooks(): Hook<FlagValue>[] {
-    return this._hooks;
-  }
-
-  clearHooks(): this {
-    this._hooks = [];
-    return this;
-  }
-
   async setContext(context: EvaluationContext): Promise<void> {
     const oldContext = this._context;
     this._context = context;
     await this._defaultProvider?.onContextChange?.(oldContext, context);
   }
 
+  getContext(): EvaluationContext {
+    return this._context;
+  }
+
   /**
    * A factory function for creating new named OpenFeature clients. Clients can contain
    * their own state (e.g. logger, hook, context). Multiple clients can be used

Diff for: packages/client/src/provider/index.ts

@@ -0,0 +1,2 @@
+export * from './provider';
+export * from './no-op-provider';

Diff for: packages/client/src/no-op-provider.ts renamed to packages/client/src/provider/no-op-provider.ts

@@ -1,5 +1,5 @@
 import { JsonValue, ProviderStatus, ResolutionDetails } from '@openfeature/shared';
-import { Provider } from './types';
+import { Provider } from './provider';
 
 const REASON_NO_OP = 'No-op';
 

Diff for: packages/client/src/provider/provider.ts

@@ -0,0 +1,65 @@
+import { CommonProvider, EvaluationContext, Hook, JsonValue, Logger, ResolutionDetails } from '@openfeature/shared';
+
+/**
+ * Interface that providers must implement to resolve flag values for their particular
+ * backend or vendor.
+ *
+ * Implementation for resolving all the required flag types must be defined.
+ */
+export interface Provider extends CommonProvider {
+  /**
+   * A provider hook exposes a mechanism for provider authors to register hooks
+   * to tap into various stages of the flag evaluation lifecycle. These hooks can
+   * be used to perform side effects and mutate the context for purposes of the
+   * provider. Provider hooks are not configured or controlled by the application author.
+   */
+  readonly hooks?: Hook[];
+
+  /**
+   * A handler function to reconcile changes when the static context.
+   * Called by the SDK when the context is changed.
+   * @param oldContext
+   * @param newContext
+   */
+  onContextChange?(oldContext: EvaluationContext, newContext: EvaluationContext): Promise<void>;
+
+  /**
+   * Resolve a boolean flag and its evaluation details.
+   */
+  resolveBooleanEvaluation(
+    flagKey: string,
+    defaultValue: boolean,
+    context: EvaluationContext,
+    logger: Logger
+  ): ResolutionDetails<boolean>;
+
+  /**
+   * Resolve a string flag and its evaluation details.
+   */
+  resolveStringEvaluation(
+    flagKey: string,
+    defaultValue: string,
+    context: EvaluationContext,
+    logger: Logger
+  ): ResolutionDetails<string>;
+
+  /**
+   * Resolve a numeric flag and its evaluation details.
+   */
+  resolveNumberEvaluation(
+    flagKey: string,
+    defaultValue: number,
+    context: EvaluationContext,
+    logger: Logger
+  ): ResolutionDetails<number>;
+
+  /**
+   * Resolve and parse an object flag and its evaluation details.
+   */
+  resolveObjectEvaluation<T extends JsonValue>(
+    flagKey: string,
+    defaultValue: T,
+    context: EvaluationContext,
+    logger: Logger
+  ): ResolutionDetails<T>;
+}