Converts an array of objects to a comma-separated values (CSV) string that contains only the columns
specified.
- Use
Array.prototype.join()
to combine all the names incolumns
to create the first row, using the provideddelimiter
. - Use
Array.prototype.map()
andArray.prototype.reduce()
to create a row for each object. Substitute non-existent values with empty strings and only mapping values incolumns
. - Use
Array.prototype.join()
to combine all rows into a string, separating each row with a newline (\n
). - Omit the third argument,
delimiter
, to use a default delimiter of','
.
代码实现
const JSONtoCSV = (arr, columns, delimiter = ',') =>
[
columns.join(delimiter),
...arr.map(obj =>
columns.reduce(
(acc, key) =>
`${acc}${!acc.length ? '' : delimiter}"${!obj[key] ? '' : obj[key]}"`,
''
)
),
].join('\n');
JSONtoCSV(
[{ a: 1, b: 2 }, { a: 3, b: 4, c: 5 }, { a: 6 }, { b: 7 }],
['a', 'b']
); // 'a,b\n"1","2"\n"3","4"\n"6",""\n"","7"'
JSONtoCSV(
[{ a: 1, b: 2 }, { a: 3, b: 4, c: 5 }, { a: 6 }, { b: 7 }],
['a', 'b'],
';'
); // 'a;b\n"1";"2"\n"3";"4"\n"6";""\n"";"7"'