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JSONtoCSV

TS JS Deno

Converts an array of objects to a comma-separated values (CSV) string that contains only the columns specified.

Use Array.prototype.join(delimiter) 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 ,.

typescript
const JSONtoCSV = (arr: any[], columns: string[], delimiter = ",") =>
[
columns.join(delimiter),
...arr.map((obj) =>
columns.reduce(
(acc, key) =>
`${acc}${!acc.length ? "" : delimiter}"${!obj[key] ? "" : obj[key]}"`,
""
)
),
].join("\n");
typescript
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"'