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12 | Legacy Frameworks |
import current from '/version.js';
Over the years, many frameworks have been released. Some were popular years ago but have waned in recent years. There are still many deployments using these frameworks and it is oftentimes esasier to continue maintenance than to rewrite using modern web techniques.
SheetJS libraries strive to maintain broad browser and JS engine compatibility.
Integration
The "Standalone Browser Scripts" section has
instructions for obtaining or referencing the standalone scripts. These are
designed to be referenced with <script>
tags.
Frameworks
KnockoutJS
KnockoutJS was a popular MVVM framework.
The Live demo shows a view model that is updated with file data and exported to spreadsheets.
State
Arrays of arrays are the simplest data structure for representing worksheets.
var aoa = [
[1, 2], // A1 = 1, B1 = 2
[3, 4] // A1 = 3, B1 = 4
];
ko.observableArray
should be used to create the view model:
function ViewModel() {
/* use an array of arrays */
this.aoa = ko.observableArray([ [1,2], [3,4] ]);
}
/* create model */
var model = new ViewModel();
ko.applyBindings(model);
XLSX.utils.sheet_to_json
with header: 1
generates data for the model:
/* 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);
XLSX.utils.aoa_to_sheet
generates worksheets from the model:
var aoa = model.aoa();
var ws = XLSX.utils.aoa_to_sheet(aoa);
Data Binding
data-bind="foreach: ..."
provides a simple approach for binding to TABLE
:
<table data-bind="foreach: aoa">
<tr data-bind="foreach: $data">
<td><span data-bind="text: $data"></span></td>
</tr>
</table>
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>