feat(plugins): csv and json import

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

packages/plugin-sdk/src/csv.ts

@@ -0,0 +1,82 @@
+export type CsvDelimiter = "," | ";" | "\t";
+
+function detectDelimiter(text: string): CsvDelimiter {
+  const counts: Record<CsvDelimiter, number> = { ",": 0, ";": 0, "\t": 0 };
+  let inQuotes = false;
+  for (const ch of text) {
+    if (ch === '"') inQuotes = !inQuotes;
+    else if (!inQuotes) {
+      if (ch === "\n" || ch === "\r") break;
+      if (ch === "," || ch === ";" || ch === "\t") counts[ch]++;
+    }
+  }
+  let best: CsvDelimiter = ",";
+  for (const d of [";", "\t"] as const) if (counts[d] > counts[best]) best = d;
+  return best;
+}
+
+/** RFC 4180 parser. Strips a BOM, auto-detects the delimiter from the header line, skips blank lines. */
+export function parseCsv(text: string, opts: { delimiter?: CsvDelimiter } = {}): string[][] {
+  if (text.charCodeAt(0) === 0xfeff) text = text.slice(1);
+  const delim = opts.delimiter ?? detectDelimiter(text);
+  const rows: string[][] = [];
+  let row: string[] = [];
+  let field = "";
+  let quoted = false; // current field was quoted
+  let inQuotes = false;
+  let pending = false; // something has been read for the current row
+
+  const endField = () => {
+    row.push(field);
+    field = "";
+  };
+  const endRow = () => {
+    const blank = row.length === 0 && field === "" && !quoted;
+    if (!blank) {
+      endField();
+      rows.push(row);
+    }
+    row = [];
+    field = "";
+    quoted = false;
+    pending = false;
+  };
+
+  for (let i = 0; i < text.length; i++) {
+    const ch = text[i]!;
+    if (inQuotes) {
+      if (ch === '"') {
+        if (text[i + 1] === '"') {
+          field += '"';
+          i++;
+        } else inQuotes = false;
+      } else field += ch;
+    } else if (ch === '"' && field === "" && !quoted) {
+      inQuotes = true;
+      quoted = true;
+      pending = true;
+    } else if (ch === delim) {
+      endField();
+      quoted = false;
+      pending = true;
+    } else if (ch === "\r" || ch === "\n") {
+      if (ch === "\r" && text[i + 1] === "\n") i++;
+      endRow();
+    } else {
+      field += ch;
+      pending = true;
+    }
+  }
+  if (pending || field !== "" || row.length > 0) endRow();
+  return rows;
+}
+
+function quoteCell(s: string, single: boolean): string {
+  if (s === "" ? single : /[",;\t\r\n]/.test(s) || s !== s.trim()) return `"${s.replaceAll('"', '""')}"`;
+  return s;
+}
+
+/** Serialises with `,` and `\r\n`, quoting only where needed. */
+export function toCsv(rows: string[][]): string {
+  return rows.map((r) => r.map((c) => quoteCell(c, r.length === 1)).join(",") + "\r\n").join("");
+}

packages/plugin-sdk/test/csv.test.ts

@@ -0,0 +1,24 @@
+import { describe, expect, test } from "bun:test";
+import { parseCsv, toCsv } from "../src/csv.ts";
+
+describe("csv codec", () => {
+  test("round-trips awkward cells", () => {
+    const x = [["a", "b,c", 'q"uote', "line\nbreak", "cr\r\nlf", "", "🐉"], ["", "", "", "", "", "", ""], ["only"]];
+    expect(parseCsv(toCsv(x))).toEqual(x);
+  });
+  test("toCsv uses CRLF and quotes as needed", () => {
+    expect(toCsv([["a", "b c"], ["x,y", 'z"']])).toBe('a,b c\r\n"x,y","z"""\r\n');
+  });
+  test("strips BOM and detects semicolon / tab", () => {
+    expect(parseCsv("a;b\n1;2\n")).toEqual([["a", "b"], ["1", "2"]]);
+    expect(parseCsv("a\tb\n1\t2")).toEqual([["a", "b"], ["1", "2"]]);
+  });
+  test("explicit delimiter wins; delimiters inside quoted header are ignored", () => {
+    expect(parseCsv('"a;b;c",d\n1,2', {})).toEqual([["a;b;c", "d"], ["1", "2"]]);
+    expect(parseCsv("a,b;c\n1,2;3", { delimiter: ";" })).toEqual([["a,b", "c"], ["1,2", "3"]]);
+  });
+  test("handles CRLF, blank trailing lines, and empty input", () => {
+    expect(parseCsv("a,b\r\n1,2\r\n\r\n")).toEqual([["a", "b"], ["1", "2"]]);
+    expect(parseCsv("")).toEqual([]);
+  });
+});