xsheetjs/docbits/22_ingress.md

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### Processing JSON and JS Data
JSON and JS data tend to represent single worksheets. This section will use a
few utility functions to generate workbooks:
_Create a new Worksheet_
```js
var workbook = XLSX.utils.book_new();
```
The `book_new` utility function creates an empty workbook with no worksheets.
_Append a Worksheet to a Workbook_
```js
XLSX.utils.book_append_sheet(workbook, worksheet, sheet_name);
```
The `book_append_sheet` utility function appends a worksheet to the workbook.
The third argument specifies the desired worksheet name. Multiple worksheets can
be added to a workbook by calling the function multiple times.
#### API
_Create a worksheet from an array of arrays of JS values_
```js
var worksheet = XLSX.utils.aoa_to_sheet(aoa, opts);
```
The `aoa_to_sheet` utility function walks an "array of arrays" in row-major
order, generating a worksheet object. The following snippet generates a sheet
with cell `A1` set to the string `A1`, cell `B1` set to `B2`, etc:
```js
var worksheet = XLSX.utils.aoa_to_sheet([
["A1", "B1", "C1"],
["A2", "B2", "C2"],
["A3", "B3", "C3"]
])
```
["Array of Arrays Input"](#array-of-arrays-input) describes the function and the
optional `opts` argument in more detail.
_Create a worksheet from an array of JS objects_
```js
var worksheet = XLSX.utils.json_to_sheet(jsa, opts);
```
The `json_to_sheet` utility function walks an array of JS objects in order,
generating a worksheet object. By default, it will generate a header row and
one row per object in the array. The optional `opts` argument has settings to
control the column order and header output.
["Array of Objects Input"](#array-of-arrays-input) describes the function and
the optional `opts` argument in more detail.
#### Examples
["Zen of SheetJS"](#the-zen-of-sheetjs) contains a detailed example "Get Data
from a JSON Endpoint and Generate a Workbook"
The [`database` demo](/demos/database/) includes examples of working with
databases and query results.
### Processing HTML Tables
#### API
_Create a worksheet by scraping an HTML TABLE in the page_
```js
var worksheet = XLSX.utils.table_to_sheet(dom_element, opts);
```
The `table_to_sheet` utility function takes a DOM TABLE element and iterates
through the rows to generate a worksheet. The `opts` argument is optional.
["HTML Table Input"](#html-table-input) describes the function in more detail.
_Create a workbook by scraping an HTML TABLE in the page_
```js
var workbook = XLSX.utils.table_to_book(dom_element, opts);
```
The `table_to_book` utility function follows the same logic as `table_to_sheet`.
After generating a worksheet, it creates a blank workbook and appends the
spreadsheet.
The options argument supports the same options as `table_to_sheet`, with the
addition of a `sheet` property to control the worksheet name. If the property
is missing or no options are specified, the default name `Sheet1` is used.
#### Examples
Here are a few common scenarios (click on each subtitle to see the code):
<details>
<summary><b>HTML TABLE element in a webpage</b> (click to show)</summary>
```html
<!-- include the standalone script and shim. this uses the UNPKG CDN -->
<script src="https://unpkg.com/xlsx/dist/shim.min.js"></script>
<script src="https://unpkg.com/xlsx/dist/xlsx.full.min.js"></script>
<!-- example table with id attribute -->
<table id="tableau">
<tr><td>Sheet</td><td>JS</td></tr>
<tr><td>12345</td><td>67</td></tr>
</table>
<!-- this block should appear after the table HTML and the standalone script -->
<script type="text/javascript">
var workbook = XLSX.utils.table_to_book(document.getElementById("tableau"));
/* DO SOMETHING WITH workbook HERE */
</script>
```
Multiple tables on a web page can be converted to individual worksheets:
```js
/* create new workbook */
var workbook = XLSX.utils.book_new();
/* convert table "table1" to worksheet named "Sheet1" */
var sheet1 = XLSX.utils.table_to_sheet(document.getElementById("table1"));
XLSX.utils.book_append_sheet(workbook, sheet1, "Sheet1");
/* convert table "table2" to worksheet named "Sheet2" */
var sheet2 = XLSX.utils.table_to_sheet(document.getElementById("table2"));
XLSX.utils.book_append_sheet(workbook, sheet2, "Sheet2");
/* workbook now has 2 worksheets */
```
Alternatively, the HTML code can be extracted and parsed:
```js
var htmlstr = document.getElementById("tableau").outerHTML;
var workbook = XLSX.read(htmlstr, {type:"string"});
```
</details>
<details>
<summary><b>Chrome/Chromium Extension</b> (click to show)</summary>
The [`chrome` demo](demos/chrome/) shows a complete example and details the
required permissions and other settings.
In an extension, it is recommended to generate the workbook in a content script
and pass the object back to the extension:
```js
/* in the worker script */
chrome.runtime.onMessage.addListener(function(msg, sender, cb) {
/* pass a message like { sheetjs: true } from the extension to scrape */
if(!msg || !msg.sheetjs) return;
/* create a new workbook */
var workbook = XLSX.utils.book_new();
/* loop through each table element */
var tables = document.getElementsByTagName("table")
for(var i = 0; i < tables.length; ++i) {
var worksheet = XLSX.utils.table_to_sheet(tables[i]);
XLSX.utils.book_append_sheet(workbook, worksheet, "Table" + i);
}
/* pass back to the extension */
return cb(workbook);
});
```
</details>