feat: cancellation support

lib/src/relewise.client.ts

@@ -3,6 +3,7 @@ import version from './version';
 
 export interface RelewiseClientOptions {
     serverUrl?: string;
+    useCancellation?: boolean;
 }
 
 export class ProblemDetailsError extends Error {
@@ -28,8 +29,29 @@ export interface HttpProblemDetails {
 }
 
 export abstract class RelewiseClient {
+    private requestDictionary: { [requestUrl: string]: AbortController | null } = {};
+
+    private ensureAbortSignal(requestUrl: string): AbortSignal {
+        let abortController = this.requestDictionary[requestUrl];
+        if (abortController) {
+            abortController.abort();
+        }
+
+        abortController = new AbortController();
+        this.requestDictionary[requestUrl] = abortController;
+
+        return abortController.signal;
+    }
+
+    private clearAbortSignal(requestUrl: string) {
+        this.requestDictionary[requestUrl] = null;
+        delete this.requestDictionary[requestUrl];
+    }
+
     private readonly _serverUrl: string = 'https://api.relewise.com';
     private readonly _urlPath: string = 'v1';
+    private readonly apiKeyHeader = `APIKey ${this.apiKey}`;
+    private readonly useCancellation: boolean = false;
 
     constructor(protected readonly datasetId: string, protected readonly apiKey: string, options?: RelewiseClientOptions) {
         if (!datasetId) throw new Error('Dataset id cannot be null or empty. Please contact Relewise if you don\'t have an account already or would like a free demo license');
@@ -38,29 +60,39 @@ export abstract class RelewiseClient {
         if (options?.serverUrl) {
             this._serverUrl = options.serverUrl;
         }
+
+        this.useCancellation = options?.useCancellation ?? false;
     }
 
     public get serverUrl(): string {
         return this._serverUrl;
     }
 
     protected async request<TRequest, TResponse>(name: string, data: TRequest): Promise<TResponse | undefined> {
-        const apiKeyHeader = `APIKey ${this.apiKey}`;
         const requestUrl = this.createRequestUrl(this._serverUrl, this.datasetId, this._urlPath, name);
 
         const response = await fetch(requestUrl, {
             method: 'POST',
             headers: {
-                Authorization: apiKeyHeader,
+                Authorization: this.apiKeyHeader,
                 'Content-Type': 'application/json',
                 'X-Relewise-Version': version.tag,
             },
             body: JSON.stringify(data),
+            ...(this.useCancellation && { signal: this.ensureAbortSignal(requestUrl) }),
         });
 
         if (!response.ok) {
             let responseMessage = null;
-            try { responseMessage = await response.json(); } catch (_) { console.log(responseMessage)}
+            try { 
+                responseMessage = await response.json();
+            } catch (_) { 
+                console.log(responseMessage)
+            } finally {
+                if (this.useCancellation) {
+                    this.clearAbortSignal(requestUrl);
+                }
+            }
 
             throw new ProblemDetailsError('Error when calling the Relewise API. Read more in the details property if there is error response or look in the network tab.', responseMessage);
         }