refactor(utils): categorize functions into separate files (#6773)

packages/docusaurus-utils/src/jsUtils.ts

@@ -0,0 +1,88 @@
+/**
+ * Copyright (c) Facebook, Inc. and its affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+import type {ReportingSeverity} from '@docusaurus/types';
+import logger from '@docusaurus/logger';
+
+export function removeSuffix(str: string, suffix: string): string {
+  if (suffix === '') {
+    return str; // always returns "" otherwise!
+  }
+  return str.endsWith(suffix) ? str.slice(0, -suffix.length) : str;
+}
+
+export function removePrefix(str: string, prefix: string): string {
+  return str.startsWith(prefix) ? str.slice(prefix.length) : str;
+}
+
+export function getElementsAround<T>(
+  array: T[],
+  aroundIndex: number,
+): {
+  next: T | undefined;
+  previous: T | undefined;
+} {
+  const min = 0;
+  const max = array.length - 1;
+  if (aroundIndex < min || aroundIndex > max) {
+    throw new Error(
+      `Valid "aroundIndex" for array (of size ${array.length}) are between ${min} and ${max}, but you provided ${aroundIndex}.`,
+    );
+  }
+  const previous = aroundIndex === min ? undefined : array[aroundIndex - 1];
+  const next = aroundIndex === max ? undefined : array[aroundIndex + 1];
+  return {previous, next};
+}
+
+export async function mapAsyncSequential<T, R>(
+  array: T[],
+  action: (t: T) => Promise<R>,
+): Promise<R[]> {
+  const results: R[] = [];
+  for (const t of array) {
+    const result = await action(t);
+    results.push(result);
+  }
+  return results;
+}
+
+export async function findAsyncSequential<T>(
+  array: T[],
+  predicate: (t: T) => Promise<boolean>,
+): Promise<T | undefined> {
+  for (const t of array) {
+    if (await predicate(t)) {
+      return t;
+    }
+  }
+  return undefined;
+}
+
+export function reportMessage(
+  message: string,
+  reportingSeverity: ReportingSeverity,
+): void {
+  switch (reportingSeverity) {
+    case 'ignore':
+      break;
+    case 'log':
+      logger.info(message);
+      break;
+    case 'warn':
+      logger.warn(message);
+      break;
+    case 'error':
+      logger.error(message);
+      break;
+    case 'throw':
+      throw new Error(message);
+    default:
+      throw new Error(
+        `Unexpected "reportingSeverity" value: ${reportingSeverity}.`,
+      );
+  }
+}