@std/csv

import { parse } from "@std/csv/parse";
import { assertEquals } from "@std/assert";

const string = "a,b,c\nd,e,f";

// 解析为二维数组（默认）
assertEquals(parse(string, { skipFirstRow: false }), [["a", "b", "c"], [
  "d",
  "e",
  "f",
]]);

// 将含有表头的 csv 文件解析为对象数组
assertEquals(parse(string, { skipFirstRow: true }), [{
  a: "d",
  b: "e",
  c: "f",
}]);

// 使用自定义列名解析
assertEquals(parse(string, { columns: ["x", "y", "z"] }), [
  { x: "a", y: "b", z: "c" },
  { x: "d", y: "e", z: "f" },
]);

// 解析制表符分隔的值
const tsvString = "name\tage\tcity\njohn\t30\tnew york\nmary\t25\tlos angeles";
assertEquals(parse(tsvString, { separator: "\t", skipFirstRow: true }), [
  { name: "john", age: "30", city: "new york" },
  { name: "mary", age: "25", city: "los angeles" },
]);

// 解析带有注释的 CSV 文件
const csvWithComments =
  "# 这是注释\nname,age,city\n# 另一条注释\njohn,30,new york\nmary,25,los angeles";
assertEquals(parse(csvWithComments, { comment: "#", skipFirstRow: true }), [
  { name: "john", age: "30", city: "new york" },
  { name: "mary", age: "25", city: "los angeles" },
]);

import { CsvParseStream } from "@std/csv/parse-stream";
import { assertEquals } from "@std/assert";

// 从流中解析（适用于大文件）
const source = ReadableStream.from([
  "name,age,city\n",
  "john,30,new york\n",
  "mary,25,los angeles\n",
]);

const csvStream = source
  .pipeThrough(new CsvParseStream({ skipFirstRow: true }));

const records = await Array.fromAsync(csvStream);
assertEquals(records, [
  { name: "john", age: "30", city: "new york" },
  { name: "mary", age: "25", city: "los angeles" },
]);

// 或者逐条处理记录
// for await (const record of csvStream) {
//   console.log(record);
// }

import { stringify } from "@std/csv/stringify";
import { assertEquals } from "@std/assert";

// 将二维数组转换为 CSV
const arrayData = [["name", "age", "city"], ["john", "30", "new york"], [
  "mary",
  "25",
  "los angeles",
]];
const csvString = stringify(arrayData);
assertEquals(
  csvString,
  "name,age,city\r\njohn,30,new york\r\nmary,25,los angeles\r\n",
);

// 将对象数组转换为 CSV
const objectData = [
  { name: "john", age: "30", city: "new york" },
  { name: "mary", age: "25", city: "los angeles" },
];

// 使用对象数组时，必须指定要使用的列
const customColumns = stringify(objectData, {
  columns: ["city", "name", "age"],
});
assertEquals(
  customColumns,
  "city,name,age\r\nnew york,john,30\r\nlos angeles,mary,25\r\n",
);

import { CsvStringifyStream } from "@std/csv/stringify-stream";
import { assertEquals } from "@std/assert";

async function writeCsvToTempFile(): Promise<string> {
  const path = await Deno.makeTempFile();
  using file = await Deno.open(path, { write: true });

  const readable = ReadableStream.from([
    { id: 1, name: "one" },
    { id: 2, name: "two" },
    { id: 3, name: "three" },
  ]);

  await readable
    .pipeThrough(new CsvStringifyStream({ columns: ["id", "name"] }))
    .pipeThrough(new TextEncoderStream())
    .pipeTo(file.writable);

  return path;
}

const path = await writeCsvToTempFile();
const content = await Deno.readTextFile(path);
assertEquals(content, "id,name\r\n1,one\r\n2,two\r\n3,three\r\n");

field1, field2, field3;

normal string,"quoted-field"

[`normal string`, `quoted-field`];

"the ""word"" is true","a ""quoted-field"""

[`the "word" is true`, `a "quoted-field"`];

"Multi-line
field","comma is ,"

[
  `Multi-line
field`,
  `comma is ,`,
];

deno add jsr:@std/csv