sheetjs-clone/docbits/82_util.md

## Utility Functions

The `sheet_to_*` functions accept a worksheet and an optional options object.

The `*_to_sheet` functions accept a data object and an optional options object.

The examples are based on the following worksheet:

```
XXX| A | B | C | D | E | F | G |
---+---+---+---+---+---+---+---+
 1 | S | h | e | e | t | J | S |
 2 | 1 | 2 | 3 | 4 | 5 | 6 | 7 |
 3 | 2 | 3 | 4 | 5 | 6 | 7 | 8 |
```

### Array of Arrays Input

`XLSX.utils.aoa_to_sheet` takes an array of arrays of JS values and returns a
worksheet resembling the input data.  Numbers, Booleans and Strings are stored
as the corresponding styles.  Dates are stored as date or numbers.  Array holes
and explicit `undefined` values are skipped.  `null` values may be stubbed. All
other values are stored as strings.  The function takes an options argument:

| Option Name |  Default | Description                                         |
| :---------- | :------: | :-------------------------------------------------- |
| dateNF      |  fmt 14  | Use specified date format in string output          |
| cellDates   |  false   | Store dates as type `d` (default is `n`)            |
| sheetStubs  |  false   | Create cell objects of type `z` for `null` values   |

To generate the example sheet:

```js
var ws = XLSX.utils.aoa_to_sheet([
	"SheetJS".split(""),
	[1,2,3,4,5,6,7],
	[2,3,4,5,6,7,8]
]);
```

### HTML Table Input

`XLSX.utils.table_to_sheet` takes a table DOM element and returns a worksheet
resembling the input table.  Numbers are parsed.  All other data will be stored
as strings.

`XLSX.utils.table_to_book` produces a minimal workbook based on the worksheet.

To generate the example sheet, start with the HTML table:

```html
<table id="sheetjs">
<tr><td>S</td><td>h</td><td>e</td><td>e</td><td>t</td><td>J</td><td>S</td></tr>
<tr><td>1</td><td>2</td><td>3</td><td>4</td><td>5</td><td>6</td><td>7</td></tr>
<tr><td>2</td><td>3</td><td>4</td><td>5</td><td>6</td><td>7</td><td>8</td></tr>
</table>
```

To process the table:

```js
var tbl = document.getElementById('sheetjs');
var wb = XLSX.utils.table_to_book(tbl);
```

Note: `XLSX.read` can handle HTML represented as strings.

### Formulae Output

`XLSX.utils.sheet_to_formulae` generates an array of commands that represent
how a person would enter data into an application.  Each entry is of the form
`A1-cell-address=formula-or-value`.  String literals are prefixed with a `'` in
accordance with Excel.  For the example sheet:

```js
> var o = XLSX.utils.sheet_to_formulae(ws);
> o.filter(function(v, i) { return i % 5 === 0; });
[ 'A1=\'S', 'F1=\'J', 'D2=4', 'B3=3', 'G3=8' ]
```

### Delimiter-Separated Output

As an alternative to the `writeFile` CSV type, `XLSX.utils.sheet_to_csv` also
produces CSV output.  The function takes an options argument:

| Option Name |  Default | Description                                         |
| :---------- | :------: | :-------------------------------------------------- |
| FS          |  `","`   | "Field Separator"  delimiter between fields         |
| RS          |  `"\n"`  | "Record Separator" delimiter between rows           |
| dateNF      |  fmt 14  | Use specified date format in string output          |
| strip       |  false   | Remove trailing field separators in each record **  |
| blankrows   |  true    | Include blank lines in the CSV output               |

- `strip` will remove trailing commas from each line under default `FS/RS`
- blankrows must be set to `false` to skip blank lines.

For the example sheet:

```js
> console.log(XLSX.utils.sheet_to_csv(ws));
S,h,e,e,t,J,S
1,2,3,4,5,6,7
2,3,4,5,6,7,8
> console.log(XLSX.utils.sheet_to_csv(ws, {FS:"\t"}));
S	h	e	e	t	J	S
1	2	3	4	5	6	7
2	3	4	5	6	7	8
> console.log(X.utils.sheet_to_csv(_ws,{FS:":",RS:"|"}));
S:h:e:e:t:J:S|1:2:3:4:5:6:7|2:3:4:5:6:7:8|
```

#### UTF-16 Unicode Text

The `txt` output type uses the tab character as the field separator.  If the
codepage library is available (included in the full distribution but not core),
the output will be encoded in codepage `1200` and the BOM will be prepended.

### JSON

`XLSX.utils.sheet_to_json` and the alias `XLSX.utils.sheet_to_row_object_array`
generate different types of JS objects.  The function takes an options argument:

| Option Name |  Default | Description                                         |
| :---------- | :------: | :-------------------------------------------------- |
| raw         | `false`  | Use raw values (true) or formatted strings (false)  |
| range       | from WS  | Override Range (see table below)                    |
| header      |          | Control output format (see table below)             |
| dateNF      |  fmt 14  | Use specified date format in string output          |
| defval      |          | Use specified value in place of null or undefined   |
| blankrows   |    **    | Include blank lines in the output **                |

- `raw` only affects cells which have a format code (`.z`) field or a formatted
  text (`.w`) field.
- If `header` is specified, the first row is considered a data row; if `header`
  is not specified, the first row is the header row and not considered data.
- When `header` is not specified, the conversion will automatically disambiguate
  header entries by affixing `_` and a count starting at `1`.  For example, if
  three columns have header `foo` the output fields are `foo`, `foo_1`, `foo_2`
- `null` values are returned when `raw` is true but are skipped when false.
- If `defval` is not specified, null and undefined values are skipped normally.
  If specified, all null and undefined points will be filled with `defval`
- When `header` is `1`, the default is to generate blank rows.  `blankrows` must
  be set to `false` to skip blank rows.
- When `header` is not `1`, the default is to skip blank rows.  `blankrows` must
  be truthy to generate blank rows

`range` is expected to be one of:

| `range`          | Description                                               |
| :--------------- | :-------------------------------------------------------- |
| (number)         | Use worksheet range but set starting row to the value     |
| (string)         | Use specified range (A1-style bounded range string)       |
| (default)        | Use worksheet range (`ws['!ref']`)                        |

`header` is expected to be one of:

| `header`         | Description                                               |
| :--------------- | :-------------------------------------------------------- |
| `1`              | Generate an array of arrays                               |
| `"A"`            | Row object keys are literal column labels                 |
| array of strings | Use specified strings as keys in row objects              |
| (default)        | Read and disambiguate first row as keys                   |

If header is not `1`, the row object will contain the non-enumerable property
`__rowNum__` that represents the row of the sheet corresponding to the entry.

For the example sheet:

```js
> console.log(X.utils.sheet_to_json(_ws));
[ { S: 1, h: 2, e: 3, e_1: 4, t: 5, J: 6, S_1: 7 },
  { S: 2, h: 3, e: 4, e_1: 5, t: 6, J: 7, S_1: 8 } ]

> console.log(X.utils.sheet_to_json(_ws, {header:1}));
[ [ 'S', 'h', 'e', 'e', 't', 'J', 'S' ],
  [ 1, 2, 3, 4, 5, 6, 7 ],
  [ 2, 3, 4, 5, 6, 7, 8 ] ]

> console.log(X.utils.sheet_to_json(_ws, {header:"A"}));
[ { A: 'S', B: 'h', C: 'e', D: 'e', E: 't', F: 'J', G: 'S' },
  { A: 1, B: 2, C: 3, D: 4, E: 5, F: 6, G: 7 },
  { A: 2, B: 3, C: 4, D: 5, E: 6, F: 7, G: 8 } ]
> console.log(X.utils.sheet_to_json(_ws, {header:["A","E","I","O","U","6","9"]}));
[ { '6': 'J', '9': 'S', A: 'S', E: 'h', I: 'e', O: 'e', U: 't' },
  { '6': 6, '9': 7, A: 1, E: 2, I: 3, O: 4, U: 5 },
  { '6': 7, '9': 8, A: 2, E: 3, I: 4, O: 5, U: 6 } ]
```

Example showing the effect of `raw`:

```js
> _ws['A2'].w = "1";                         // set A2 formatted string value
> console.log(X.utils.sheet_to_json(_ws, {header:1}));
[ [ 'S', 'h', 'e', 'e', 't', 'J', 'S' ],
  [ '1', 2, 3, 4, 5, 6, 7 ],                 // <-- A2 uses the formatted string
  [ 2, 3, 4, 5, 6, 7, 8 ] ]
> console.log(X.utils.sheet_to_json(_ws, {header:1, raw:true}));
[ [ 'S', 'h', 'e', 'e', 't', 'J', 'S' ],
  [ 1, 2, 3, 4, 5, 6, 7 ],                   // <-- A2 uses the raw value
  [ 2, 3, 4, 5, 6, 7, 8 ] ]
```