JSON topic
Turn a worksheet into JSON, or into plain Dart maps you can hand to
jsonEncode, an API client, or a model constructor. The SheetJson extension
adds SheetJson.rowsAsMaps and SheetJson.toJson to a Sheet, and ExcelJson
adds ExcelJson.toJson to an Excel workbook.
final excel = Excel.decodeBytes(bytes);
// Read a sheet as header-keyed maps, using row 0 for the keys.
for (final row in excel['People'].rowsAsMaps()) {
print('${row['name']} is ${row['age']}');
}
// Or serialise straight to a JSON string.
final json = excel['People'].toJson(); // [{"name":"Alice","age":30}]
final all = excel.toJson(pretty: true); // every sheet, keyed by name
Every map holds a key for each column in the sheet's used width, so all rows
share the same keys and an empty cell reads as null. An empty header cell
falls back to its column letter (A, B, ...) and a repeated name gets a _2
suffix, so no column is ever dropped. Rows that are entirely empty are skipped
unless you pass skipEmptyRows: false.
Numbers and booleans keep their Dart types; dates and times become ISO-8601
strings (2024-01-31, 2024-01-31T09:30:00, 09:30:00) because JSON has no
date type. A formula cell exports its cached result, or the formula text with a
leading = when there is no cached value or you pass formulasAsText: true.
Pass headerRow to take the keys from a different row, or headerRow: null for
an array of arrays with no header at all:
final grid = sheet.toJson(headerRow: null); // [["name","age"],["Alice",30]]
final later = sheet.toJson(headerRow: 2); // skip a two-line preamble