XLSX support with ExcelJS

src/dependencies.js

@@ -16,3 +16,4 @@ export const vegaliteApi = dependency("vega-lite-api", "5.0.0", "build/vega-lite
 export const arrow = dependency("apache-arrow", "4.0.1", "Arrow.es2015.min.js");
 export const arquero = dependency("arquero", "4.8.4", "dist/arquero.min.js");
 export const topojson = dependency("topojson-client", "3.1.0", "dist/topojson-client.min.js");
+export const exceljs = dependency("exceljs", "4.3.0", "dist/exceljs.min.js");

src/fileAttachment.js

@@ -1,7 +1,8 @@
 import {autoType, csvParse, csvParseRows, tsvParse, tsvParseRows} from "d3-dsv";
 import {require as requireDefault} from "d3-require";
-import {arrow, jszip} from "./dependencies.js";
+import {arrow, jszip, exceljs} from "./dependencies.js";
 import {SQLiteDatabaseClient} from "./sqlite.js";
+import {ExcelWorkbook} from "./xlsx.js";
 
 async function remote_fetch(file) {
   const response = await fetch(await file.url());
@@ -70,6 +71,10 @@ class AbstractFile {
   async html() {
     return this.xml("text/html");
   }
+  async xlsx() {
+    const [ExcelJS, buffer] = await Promise.all([requireDefault(exceljs.resolve()), this.arrayBuffer()]);
+    return new ExcelWorkbook(await new ExcelJS.Workbook().xlsx.load(buffer));
+  }
 }
 
 class FileAttachment extends AbstractFile {

src/xlsx.js

@@ -0,0 +1,99 @@
+export class ExcelWorkbook {
+  constructor(workbook) {
+    Object.defineProperty(this, "_", {value: workbook});
+  }
+  sheetNames() {
+    return this._.worksheets.map((sheet) => sheet.name);
+  }
+  sheet(name, {range, headers = false} = {}) {
+    const sheet = this._.getWorksheet(
+      typeof name === "number" ? this.sheetNames()[name] : name + ""
+    );
+    if (!sheet) throw new Error(`Sheet not found: ${name}`);
+    return extract(sheet, {range, headers});
+  }
+}
+
+function extract(sheet, {range, headers}) {
+  let [[c0, r0], [c1, r1]] = parseRange(range, sheet);
+  const seen = new Set();
+  const names = [];
+  const headerRow = headers && sheet._rows[r0++];
+  function name(n) {
+    if (!names[n]) {
+      let name = (headerRow ? valueOf(headerRow._cells[n]) : AA(n)) || AA(n);
+      while (seen.has(name)) name += "_";
+      seen.add((names[n] = name));
+    }
+    return names[n];
+  }
+  if (headerRow) for (let c = c0; c <= c1; c++) name(c);
+
+  const output = new Array(r1 - r0 + 1).fill({});
+  for (let r = r0; r <= r1; r++) {
+    const _row = sheet._rows[r];
+    if (!_row || !_row.hasValues) continue;
+    const row = (output[r - r0] = {});
+    for (let c = c0; c <= c1; c++) {
+      const value = valueOf(_row._cells[c]);
+      if (value !== null && value !== undefined) row[name(c)] = value;
+    }
+  }
+
+  output.columns = names.filter(() => true);
+  return output;
+}
+
+function valueOf(cell) {
+  if (!cell) return;
+  const {value} = cell;
+  if (value && typeof value === "object") {
+    if (value.formula) return value.result;
+    if (value.richText) return value.richText.map((d) => d.text).join("");
+    if (value.text && value.hyperlink)
+      return `<a href="${value.hyperlink}">${value.text}</a>`;
+  }
+  return value;
+}
+
+function parseRange(specifier = [], {columnCount, rowCount}) {
+  if (typeof specifier === "string") {
+    const [
+      [c0 = 0, r0 = 0] = [],
+      [c1 = columnCount - 1, r1 = rowCount - 1] = [],
+    ] = specifier.split(":").map(NN);
+    return [
+      [c0, r0],
+      [c1, r1],
+    ];
+  } else if (typeof specifier === "object") {
+    const [
+      [c0 = 0, r0 = 0] = [],
+      [c1 = columnCount - 1, r1 = rowCount - 1] = [],
+    ] = specifier;
+    return [
+      [c0, r0],
+      [c1, r1],
+    ];
+  }
+}
+
+function AA(c) {
+  let sc = "";
+  c++;
+  do {
+    sc = String.fromCharCode(64 + (c % 26 || 26)) + sc;
+  } while ((c = Math.floor((c - 1) / 26)));
+  return sc;
+}
+
+function NN(s = "") {
+  const [, sc, sr] = s.match(/^([a-zA-Z]+)?(\d+)?$/);
+  let c = undefined;
+  if (sc) {
+    c = 0;
+    for (let i = 0; i < sc.length; i++)
+      c += Math.pow(26, sc.length - i - 1) * (sc.charCodeAt(i) - 64);
+  }
+  return [c && c - 1, sr && +sr - 1];
+}

test/xlsx-test.js

@@ -0,0 +1,156 @@
+import {test} from "tap";
+import {ExcelWorkbook} from "../src/xlsx.js";
+
+function mockWorkbook(contents) {
+  return {
+    worksheets: Object.keys(contents).map((name) => ({name})),
+    getWorksheet(name) {
+      const _rows = contents[name];
+      return {
+        _rows: _rows.map((row) => ({
+          _cells: row.map((cell) => ({value: cell})),
+          hasValues: !!row.length,
+        })),
+        rowCount: _rows.length,
+        columnCount: Math.max(..._rows.map((r) => r.length)),
+      };
+    },
+  };
+}
+
+test("FileAttachment.xlsx reads sheet names", (t) => {
+  const workbook = new ExcelWorkbook(mockWorkbook({Sheet1: []}));
+  t.same(workbook.sheetNames(), ["Sheet1"]);
+  t.end();
+});
+
+test("FileAttachment.xlsx reads sheets", (t) => {
+  const workbook = new ExcelWorkbook(
+    mockWorkbook({
+      Sheet1: [
+        ["one", "two", "three"],
+        [1, 2, 3],
+      ],
+    })
+  );
+  t.same(workbook.sheet(0), [
+    {A: "one", B: "two", C: "three"},
+    {A: 1, B: 2, C: 3},
+  ]);
+  t.end();
+});
+
+test("FileAttachment.xlsx reads sheets with different types", (t) => {
+  const workbook = new ExcelWorkbook(
+    mockWorkbook({
+      Sheet1: [
+        ["one", {richText: [{text: "two"}, {text: "three"}]}],
+        [
+          {text: "link", hyperlink: "https://example.com"},
+          2,
+          {formula: "=B2*5", result: 10},
+        ],
+      ],
+    })
+  );
+  t.same(workbook.sheet(0), [
+    {A: "one", B: "twothree"},
+    {A: `<a href="https://example.com">link</a>`, B: 2, C: 10},
+  ]);
+  t.end();
+});
+
+test("FileAttachment.xlsx reads sheets with headers", (t) => {
+  const workbook = new ExcelWorkbook(
+    mockWorkbook({
+      Sheet1: [
+        [null, "one", "one", "two", "A"],
+        [   1,  null,     3,     4,   5],
+        [   6,     7,     8,     9,  10],
+      ],
+    })
+  );
+  t.same(workbook.sheet(0, {headers: true}), [
+    {A: 1, one_: 3, two: 4, A_: 5},
+    {A: 6, one: 7, one_: 8, two: 9, A_: 10},
+  ]);
+  t.end();
+});
+
+test("FileAttachment.xlsx reads sheet ranges", (t) => {
+  const workbook = new ExcelWorkbook(
+    mockWorkbook({
+      Sheet1: [
+        [0, 1, 2, 3, 4, 5, 6, 7, 8, 9],
+        [10, 11, 12, 13, 14, 15, 16, 17, 18, 19],
+        [20, 21, 22, 23, 24, 25, 26, 27, 28, 29],
+        [30, 31, 32, 33, 34, 35, 36, 37, 38, 39],
+      ],
+    })
+  );
+
+  // undefined
+  // ""
+  // []
+  const entireSheet = [
+    {A: 0, B: 1, C: 2, D: 3, E: 4, F: 5, G: 6, H: 7, I: 8, J: 9},
+    {A: 10, B: 11, C: 12, D: 13, E: 14, F: 15, G: 16, H: 17, I: 18, J: 19},
+    {A: 20, B: 21, C: 22, D: 23, E: 24, F: 25, G: 26, H: 27, I: 28, J: 29},
+    {A: 30, B: 31, C: 32, D: 33, E: 34, F: 35, G: 36, H: 37, I: 38, J: 39},
+  ];
+  t.same(workbook.sheet(0), entireSheet);
+  t.same(workbook.sheet(0, {range: ""}), entireSheet);
+  t.same(workbook.sheet(0, {range: []}), entireSheet);
+
+  // "B2:C3"
+  // [[1,1],[2,2]]
+  t.same(workbook.sheet(0, {range: "B2:C3"}), [
+    {B: 11, C: 12},
+    {B: 21, C: 22},
+  ]);
+  t.same(
+    workbook.sheet(0, {
+      range: [
+        [1, 1],
+        [2, 2],
+      ],
+    }),
+    [
+      {B: 11, C: 12},
+      {B: 21, C: 22},
+    ]
+  );
+
+  // ":C3"
+  // [,[2,2]]
+  t.same(workbook.sheet(0, {range: ":C3"}), [
+    {A: 0, B: 1, C: 2},
+    {A: 10, B: 11, C: 12},
+    {A: 20, B: 21, C: 22},
+  ]);
+  t.same(workbook.sheet(0, {range: [undefined, [2, 2]]}), [
+    {A: 0, B: 1, C: 2},
+    {A: 10, B: 11, C: 12},
+    {A: 20, B: 21, C: 22},
+  ]);
+
+  // "B2"
+  // [[1,1]]
+  t.same(workbook.sheet(0, {range: "B2"}), [
+    {B: 11, C: 12, D: 13, E: 14, F: 15, G: 16, H: 17, I: 18, J: 19},
+    {B: 21, C: 22, D: 23, E: 24, F: 25, G: 26, H: 27, I: 28, J: 29},
+    {B: 31, C: 32, D: 33, E: 34, F: 35, G: 36, H: 37, I: 38, J: 39},
+  ]);
+  t.same(workbook.sheet(0, {range: [[1, 1]]}), [
+    {B: 11, C: 12, D: 13, E: 14, F: 15, G: 16, H: 17, I: 18, J: 19},
+    {B: 21, C: 22, D: 23, E: 24, F: 25, G: 26, H: 27, I: 28, J: 29},
+    {B: 31, C: 32, D: 33, E: 34, F: 35, G: 36, H: 37, I: 38, J: 39},
+  ]);
+
+  // "2"
+  // [[,1]]
+  t.same(workbook.sheet(0, {range: "2"}), entireSheet.slice(1));
+  t.same(workbook.sheet(0, {range: [[undefined, 1]]}), entireSheet.slice(1));
+
+  t.end();
+});