Options

Every option is optional.

Option	Type	Default	Description
columns	(keyof T)[] or Record<keyof T, string>	union of record keys	Columns to emit: an array of keys, or a map of key to header label.
showHeaders	boolean	true	Whether to emit a header row.
separator	string	,	Field separator. One character.
quote	string	"	Quote character used when a field must be quoted. One character.
newline	string	\r\n	Line terminator between records.
finalNewline	boolean	false	Append a trailing newline after the last record.
quoting	'minimal' | 'all' | 'non-numeric'	minimal	minimal quotes only when required; all quotes every field; non-numeric quotes all but numbers.
format	(value, context) => unknown	none	Transform each value before it is encoded.
nullText	string	""	Text for null.
undefinedText	string	""	Text for undefined.
nanText	string	""	Text for NaN.
infinityText	string	Infinity	Text for Infinity; -Infinity becomes - followed by this.
booleans	{ true: string; false: string }	{ true: 'true', false: 'false' }	Text for boolean values.
arraySeparator	string	,	Separator used to join an array within a single cell.
bom	boolean	false	Prepend a UTF-8 byte-order mark, which helps some spreadsheet apps.
sanitizeFormulas	boolean	false	Guard string and array cells against spreadsheet formula injection.
formulaPrefix	string	'	Prefix applied by sanitizeFormulas.

Behavior

• separator and quote must be a single character, matching the parser, so encoded output round-trips. A non-single-character value throws a CsvPipeError.
• A quoted field escapes an embedded quote by doubling it, per RFC 4180.
• null, undefined, and NaN render as an empty string by default.
• A missing key and an explicit undefined are treated the same.
• An array value is joined into one cell using arraySeparator.
• A Date renders as an ISO 8601 string.
• A value that cannot be a cell (a plain object, function, or symbol) throws a CsvPipeError that names the row and column. Use format to handle such values.
• With sanitizeFormulas, any string or array cell that begins with a formula character (=, +, -, @, a tab, or a carriage return) is prefixed so a spreadsheet shows it literally.

Examples

Tab-separated values

Set separator to a tab for TSV output.

stringify([{ a: 1, b: 'x' }], { separator: '\t' });
// a	b
// 1	x

Quoting strategy

minimal (the default) quotes only when a field contains the separator, a quote, or a line break. all quotes every field; non-numeric quotes everything except numbers and bigints.

stringify([{ a: 1, b: 'x' }], { quoting: 'all' });
// "a","b"
// "1","x"

stringify([{ a: 1, b: 'x' }], { quoting: 'non-numeric' });
// "a","b"
// 1,"x"

Excel-friendly UTF-8 BOM

Some spreadsheet apps need a byte-order mark to read UTF-8 correctly. bom prepends one.

stringify([{ a: 1, b: 'x' }], { bom: true });
// a UTF-8 BOM, then:
// a,b
// 1,x

Custom booleans and empty values

stringify([{ active: true, note: null }], {
  booleans: { true: 'yes', false: 'no' },
  nullText: 'N/A'
});
// active,note
// yes,N/A

Arrays in one cell

An array value is joined into a single cell with arraySeparator.

stringify([{ tags: ['a', 'b', 'c'] }], { arraySeparator: ' | ' });
// tags
// a | b | c

See the API reference for the typed option definitions.