docs.sheetjs.com/docz/docs/06-solutions/03-processing.md

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sidebar_position: 3
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# Data Processing

The ["Common Spreadsheet Format"](/docs/csf/general) is a simple object
representation of the core concepts of a workbook.  The utility functions work
with the object representation and are intended to handle common use cases.

The [Data Input](/docs/solutions/input) and [Data Output](/docs/solutions/output) sections cover how to
read from data sources and write to data sources.

## Workbook

### Worksheets

:::note

Worksheet names are case-sensitive.

:::

_List the Worksheet names in tab order_

```js
var wsnames = workbook.SheetNames;
```

The `SheetNames` property of the workbook object is a list of the worksheet
names in "tab order".  API functions will look at this array.

_Access a Worksheet by name_

```js
var worksheet = workbook.Sheets[sheet_name];
```

The workbook object's `Sheets` property is an object whose keys are sheet names
and whose values are worksheet objects.

_Access the first Worksheet_

```js
var first_ws = workbook.Sheets[workbook.SheetNames[0]];
```

Combining the previous examples, `workbook.Sheets[workbook.SheetNames[0]]` is
the first worksheet if it exists in the workbook.


_Replace a Worksheet in place_

```js
workbook.Sheets[sheet_name] = new_worksheet;
```

The `Sheets` property of the workbook object is an object whose keys are names
and whose values are worksheet objects.  By reassigning to a property of the
`Sheets` object, the worksheet object can be changed without disrupting the
rest of the worksheet structure.

_Append a Worksheet to a Workbook_

```js
XLSX.utils.book_append_sheet(workbook, worksheet, sheet_name);
```

The [`book_append_sheet`](/docs/api/utilities/wb) utility function appends a
worksheet to the workbook.

_Append a Worksheet to a Workbook and find a unique name_

```js
var new_name = XLSX.utils.book_append_sheet(workbook, worksheet, name, true);
```

If the fourth argument is `true`, the function will try to find a new worksheet
name in case of a collision.

#### Examples

```js
var ws_name = "SheetJS";

/* Create worksheet */
var ws_data = [
  [ "S", "h", "e", "e", "t", "J", "S" ],
  [  1 ,  2 ,  3 ,  4 ,  5 ]
];
var ws = XLSX.utils.aoa_to_sheet(ws_data);

/* Create workbook */
var wb = XLSX.utils.book_new();

/* Add the worksheet to the workbook */
// highlight-next-line
XLSX.utils.book_append_sheet(wb, ws, ws_name);

/* Write to file */
XLSX.writeFile(wb, "SheetJS.xlsx");
```

### Other Properties

_Add a Defined Name_

```js
if(!workbook.Workbook) workbook.Workbook = {};
if(!workbook.Workbook.Names) workbook.Workbook.Names = [];
workbook.Workbook.Names.push({
  Name: "SourceData",
  Ref: "Sheet1!$A$1:$D$12"
});
```

This is described in more detail in ["Defined Names"](/docs/csf/features/names).

_Set Workbook Properties_

```js
if(!wb.Props) wb.Props = {};
wb.Props["Company"] = "SheetJS LLC";
```

The full set of property names, and their mapping to the Excel UI, is included
in ["File Properties"](/docs/csf/book#file-properties)

## Worksheet

### Cells

_Modify a single cell value in a Worksheet_

```js
XLSX.utils.sheet_add_aoa(worksheet, [[new_value]], { origin: address });
```

_Modify multiple cell values in a Worksheet_

```js
XLSX.utils.sheet_add_aoa(worksheet, aoa, opts);
```

The `sheet_add_aoa` utility function modifies cell values in a worksheet.  The
first argument is the worksheet object.  The second argument is an array of
arrays of values.  The `origin` key of the third argument controls where cells
will be written.  The following snippet sets `B3=1` and `E5="abc"`:

```js
XLSX.utils.sheet_add_aoa(worksheet, [
  [1],                             // <-- Write 1 to cell B3
  ,                                // <-- Do nothing in row 4
  [/*B5*/, /*C5*/, /*D5*/, "abc"]  // <-- Write "abc" to cell E5
], { origin: "B3" });
```

["Array of Arrays Input"](/docs/api/utilities#array-of-arrays-input) describes the
function and the optional `opts` argument in more detail.

#### Examples

The special origin value `-1` instructs `sheet_add_aoa` to start in column A of
the row after the last row in the range, appending the data:

```js
XLSX.utils.sheet_add_aoa(worksheet, [
  ["first row after data", 1],
  ["second row after data", 2]
], { origin: -1 });
```

### Other Properties

_Merge a group of cells_

```js
if(!worksheet["!merges"]) worksheet["!merges"] = [];
worksheet["!merges"].push(XLSX.utils.decode_range("A1:E1"));
```

The `!merges` property of a worksheet object is a list of [Cell Ranges](/docs/csf/general#cell-ranges).
The data for the cell will be taken from the top-left cell.

A range can be created with `decode_range` or specified manually:

```js
worksheet["!merges"].push({
  s: { r: 2, c: 1 }, // s ("start"): c = 1 r = 2 -> "B3"
  e: { r: 3, c: 4 }  // e ("end"):   c = 4 r = 3 -> "E4"
});
```

:::caution

This approach does not verify if two merged ranges intersect.

:::