deno-csv
Streaming API for reading and writing CSV for https://deno.land/.
Usage
Reading
Read CSV file
import { readCSV } from "https://deno.land/x/csv/mod.ts";
const f = await Deno.open("./example.csv");
for await (const row of readCSV(f)) {
console.log("row:");
for await (const cell of row) {
console.log(` cell: ${cell}`);
}
}
f.close();Read CSV file with custom separators
import { readCSV } from "https://deno.land/x/csv/mod.ts";
const f = await Deno.open("./example.csv");
const options = {
columnSeparator: ";",
lineSeparator: "\r\n",
quote: "$",
};
for await (const row of readCSV(f, options)) {
console.log("row:");
for await (const cell of row) {
console.log(` cell: ${cell}`);
}
}
f.close();Read objects from CSV file with header row
import { readCSVObjects } from "https://deno.land/x/csv/mod.ts";
const f = await Deno.open("./example.csv");
for await (const obj of readCSVObjects(f)) {
console.log(obj);
}
f.close();Read CSV file manually
import { readCSVObjects } from "https://deno.land/x/csv/mod.ts";
const f = await Deno.open("./example.csv");
let row: string[] = [];
const reader = new CSVReader(f, {
columnSeparator: "\t",
lineSeparator: "\r\n",
onCell(cell: string) {
row.push(cell);
},
onRowEnd() {
console.log(row);
row = [];
},
onEnd() {
console.log("end");
f.close();
},
onError(err) {
console.error(err);
},
});
reader.read();Writing
Write CSV file
import { writeCSV } from "https://deno.land/x/csv/mod.ts";
const f = await Deno.open("./example.csv", {
write: true,
create: true,
truncate: true,
});
const rows = [
["a", "b", "c"],
["1", "2", "3"],
];
await writeCSV(f, rows);
f.close();Write objects asynchronously to CSV file
import { writeCSVObjects } from "https://deno.land/x/csv/mod.ts";
const f = await Deno.open("./example.csv", {
write: true,
create: true,
truncate: true,
});
const header = ["a", "b", "c"];
const asyncObjectsGenerator = async function* () {
yield { a: "1", b: "2", c: "3" };
yield { a: "4", b: "5", c: "6" };
};
await writeCSVObjects(f, asyncObjectsGenerator(), { header });
f.close();Write CSV file manually
import { CSVWriter } from "https://deno.land/x/csv/mod.ts";
const f = await Deno.open("./example.csv", {
write: true,
create: true,
truncate: true,
});
const writer = new CSVWriter(f, {
columnSeparator: "\t",
lineSeparator: "\r\n",
});
await writer.writeCell("a");
await writer.writeCell("b");
await writer.writeCell("c");
await writer.nextLine();
await writer.writeCell("1");
await writer.writeCell("2");
await writer.writeCell("3");
f.close();Benchmarks
test-node-csv-parse
Read 500001 lines for 8.937 seconds
test-deno-csv-CSVReader
Read 500001 lines for 8.986 seconds
test-deno-csv-readCSVRows
Read 500001 lines for 9.425 seconds
test-deno-csv-readCSVStream
Read 500001 lines for 13.657 seconds
test-deno-csv-readCSV
Read 500001 lines for 15.814 seconds