Initial commit

src/fetchWithValidation.ts

@@ -0,0 +1,55 @@
+import { Schema, z } from 'zod';
+import fetch, { RequestInit } from 'node-fetch';
+import { isWithError, isWithReason, HttpError } from './utils';
+
+export class ExtendedError extends Error {
+  public url: string;
+
+  public status: number | null;
+
+  constructor(url: string, status: number | null, message: string) {
+    super();
+    this.url = url;
+    this.status = status;
+    this.message = message;
+  }
+}
+
+export const fetchJsonWithValidation = async <DataOut, DataIn, ErrorOut, ErrorIn>(
+  url: string,
+  schema: Schema<DataOut, z.ZodTypeDef, DataIn>,
+  options?: RequestInit,
+  errorSchema?: Schema<ErrorOut, z.ZodTypeDef, ErrorIn>,
+) => {
+  const response = await fetch(url, {
+    ...options || {},
+    headers: {
+      'Cache-Control': 'no-store, max-age=0',
+      ...(options ? options.headers : {}),
+    },
+  });
+  const text = await response.text();
+
+  // The ok read-only property of the Response interface contains a Boolean
+  // stating whether the response was successful (status in the range 200 - 299) or not.
+
+  if (!response.ok) {
+    throw new HttpError(response.status, text, 'HTTP', response.statusText);
+  }
+
+  const payload: unknown = JSON.parse(text);
+
+  try {
+    const data = schema.parse(payload);
+    return data;
+  } catch (e) {
+    if (errorSchema) {
+      const errorObj = errorSchema.parse(payload);
+      if (isWithError(errorObj) && isWithReason(errorObj.error)) {
+        throw new ExtendedError(url, response.status, errorObj.error.reason);
+      }
+    }
+    if (e instanceof Error) throw new ExtendedError(url, response.status, e.message);
+    throw e;
+  }
+};