Made sort and extract pages functions conform to the new design pattern. Standardised naming of a few variables

shared-operations/src/functions/extractPages.ts

@@ -0,0 +1,20 @@
+
+import { PdfFile } from '../wrappers/PdfFile.js';
+import { getPages } from './common/getPagesByIndex.js';
+
+export type ExtractPagesParamsType = {
+    file: PdfFile;
+    pageIndexes: string | number[];
+}
+export async function extractPages(params: ExtractPagesParamsType) {
+    const { file, pageIndexes } = params;
+    const pdfLibDocument = await file.pdfLibDocument;
+
+    var indexes = pageIndexes;
+
+    if (!Array.isArray(indexes)) {
+        indexes = parsePageIndexSpecification(indexes, pdfLibDocument.getPageCount());
+    }
+
+    return getPages(file, indexes);
+}