pbzsucks/csv.js at master · bitfalls/pbzsucks · GitHub

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"use strict";

function parseCsv(text) {
  if (text.charCodeAt(0) === 0xfeff) {
    text = text.slice(1);
  }

  const rows = [];
  let row = [];
  let field = "";
  let inQuotes = false;

  for (let i = 0; i < text.length; i += 1) {
    const ch = text[i];

    if (inQuotes) {
      if (ch === '"') {
        if (text[i + 1] === '"') {
          field += '"';
          i += 1;
        } else {
          inQuotes = false;
        }
      } else {
        field += ch;
      }
      continue;
    }

    if (ch === '"') {
      inQuotes = true;
      continue;
    }

    if (ch === ",") {
      row.push(field);
      field = "";
      continue;
    }

    if (ch === "\n") {
      row.push(field);
      rows.push(row);
      row = [];
      field = "";
      continue;
    }

    if (ch === "\r") {
      if (text[i + 1] === "\n") {
        i += 1;
      }
      row.push(field);
      rows.push(row);
      row = [];
      field = "";
      continue;
    }

    field += ch;
  }

  row.push(field);
  rows.push(row);

  if (rows.length && rows[rows.length - 1].length === 1 && rows[rows.length - 1][0] === "") {
    rows.pop();
  }

  const headers = rows.shift() || [];
  const dataRows = rows.map((r) => {
    const obj = {};
    for (let i = 0; i < headers.length; i += 1) {
      obj[headers[i]] = r[i] ?? "";
    }
    return obj;
  });

  return { headers, rows: dataRows };
}

function stringifyCsv(rows, headers) {
  const lines = [];
  lines.push(headers.join(","));

  for (const row of rows) {
    const fields = headers.map((h) => escapeCsvField(row[h] ?? ""));
    lines.push(fields.join(","));
  }

  return `${lines.join("\n")}\n`;
}

function escapeCsvField(value) {
  const str = String(value);
  if (/[",\n\r]/.test(str)) {
    return `"${str.replace(/"/g, '""')}"`;
  }
  return str;
}

export {
  parseCsv,
  stringifyCsv,
};