XLSX file attachments

.eslintrc.json

@@ -2,7 +2,7 @@
   "extends": "eslint:recommended",
   "parserOptions": {
     "sourceType": "module",
-    "ecmaVersion": 8
+    "ecmaVersion": 9
   },
   "env": {
     "browser": true,

src/fileAttachment.js

@@ -1,5 +1,6 @@
 import {require as requireDefault} from "d3-require";
 import sqlite, {SQLiteDatabaseClient} from "./sqlite.js";
+import xlsx, {XlsxWorkbook} from "./xlsx.js";
 
 async function remote_fetch(file) {
   const response = await fetch(await file.url());
@@ -62,6 +63,10 @@ class FileAttachment {
     const db = new SQL.Database(new Uint8Array(buffer));
     return new SQLiteDatabaseClient(db);
   }
+  async xlsx(options) {
+    const [XLSX, buffer] = await Promise.all([xlsx(requireDefault), this.arrayBuffer()]);
+    return new XlsxWorkbook(await XLSX.read(buffer, {cellDates: true, ...options, type: "buffer"}));
+  }
 }
 
 export function NoFileAttachments(name) {

src/xlsx.js

@@ -0,0 +1,20 @@
+let XLSX; // set lazily
+
+export default async function xslx(require) {
+  return XLSX = await require("[email protected]/dist/xlsx.mini.min.js");
+}
+
+export class XlsxWorkbook {
+  constructor(workbook) {
+    Object.defineProperties(this, {
+      _: {value: workbook}
+    });
+  }
+  sheetNames() {
+    return this._.SheetNames.slice();
+  }
+  sheet(name, options) {
+    if (!Object.prototype.hasOwnProperty.call(this._.Sheets, name)) throw new Error("unknown sheet");
+    return XLSX.utils.sheet_to_json(this._.Sheets[name], options);
+  }
+}