8ee50178f3
Correct: `Array.from()` (it’s a static method) Incorrect: `Array.join()` (doesn’t exist; it’s a prototype method) This patch uses the common `#` syntax to denote `.prototype.`.
1.1 KiB
1.1 KiB
JSONtoCSV
Converts an array of objects to a comma-separated values (CSV) string that contains only the columns specified.
Use Array.prototype.join(demiliter) to combine all the names in columns to create the first row.
Use Array.prototype.map() and Array.prototype.reduce() to create a row for each object, substituting non-existent values with empty strings and only mapping values in columns.
Use Array.prototype.join('\n') to combine all rows into a string.
Omit the third argument, delimiter, to use a default delimiter of ,.
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"'