sheetjs-clone/demos/knockout/README.md
2018-05-20 21:41:01 -04:00

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Knockout

The xlsx.core.min.js and xlsx.full.min.js scripts are designed to be dropped into web pages with script tags:

<script src="xlsx.full.min.js"></script>

Strictly speaking, there should be no need for a Knockout demo! You can proceed as you would with any other browser-friendly library.

Array of Arrays

A common data table is often stored as an array of arrays:

var aoa = [ [1,2], [3,4] ];

This neatly maps to a table with data-bind="foreach: ...":

<table data-bind="foreach: aoa">
  <tr data-bind="foreach: $data">
    <td><span data-bind="text: $data"></span></td>
  </tr>
</table>

The sheet_to_json utility function can generate array of arrays for model use:

/* starting from a `wb` workbook object, pull first worksheet */
var ws = wb.Sheets[wb.SheetNames[0]];
/* convert the worksheet to an array of arrays */
var aoa = XLSX.utils.sheet_to_json(ws, {header:1});
/* update model */
model.aoa(aoa);

Demo

The easiest observable representation is an observableArray:

var ViewModel = function() { this.aoa = ko.observableArray([[1,2],[3,4]]); };
var model = new ViewModel();
ko.applyBindings(model);

Unfortunately the nested "foreach: $data" binding is read-only. A two-way binding is possible using the $parent and $index binding context properties:

<table data-bind="foreach: aoa">
  <tr data-bind="foreach: $data">
    <td><input data-bind="value: $parent[$index()]" /></td>
  </tr>
</table>

The demo shows reading worksheets into a view model and writing models to XLSX.

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