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30-seconds-of-code/snippets/arrayToCSV.md
Isabelle Viktoria Maciohsek 15dcd4d184 Format arrayToCSV
2020-11-03 21:55:08 +02:00

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---
title: arrayToCSV
tags: array,string,intermediate
---
Converts a 2D array to a comma-separated values (CSV) string.
- Use `Array.prototype.map()` and `Array.prototype.join(delimiter)` to combine individual 1D arrays (rows) into strings.
- Use `Array.prototype.join('\n')` to combine all rows into a CSV string, separating each row with a newline.
- Omit the second argument, `delimiter`, to use a default delimiter of `,`.
```js
const arrayToCSV = (arr, delimiter = ',') =>
arr
.map(v =>
v.map(x => (isNaN(x) ? `"${x.replace(/"/g, '""')}"` : x)).join(delimiter)
)
.join('\n');
```
```js
arrayToCSV([['a', 'b'], ['c', 'd']]); // '"a","b"\n"c","d"'
arrayToCSV([['a', 'b'], ['c', 'd']], ';'); // '"a";"b"\n"c";"d"'
arrayToCSV([['a', '"b" great'], ['c', 3.1415]]);
// '"a","""b"" great"\n"c",3.1415'
```