fix(csv-parse): type the delimiter_auto score callback arguments

packages/csv-parse/lib/index.d.ts

@@ -93,9 +93,37 @@ export type ColumnOption<K = string> =
   | false
   | { name: K };
 
+export interface InfoDelimiterAuto {
+  /**
+   * The character code of the delimiter candidate being scored.
+   */
+  readonly char_code: number;
+  /**
+   * The number of occurrences of the candidate in each line.
+   */
+  readonly lines: number[];
+  /**
+   * Whether the candidate is listed in the `preferred` option.
+   */
+  readonly preferred: boolean;
+  /**
+   * The standard deviation of the occurrences across the lines.
+   */
+  readonly std: number;
+  /**
+   * The total number of occurrences of the candidate.
+   */
+  readonly total: number;
+}
+
+export type ScoringFunction = (
+  info: InfoDelimiterAuto,
+  options: OptionDelimiterAuto,
+) => number;
+
 export interface OptionDelimiterAuto {
   preferred: Record<string, number>;
-  score: () => number;
+  score: ScoringFunction;
   size: number;
 }
 

packages/csv-parse/test/option.delimiter_auto.ts

@@ -38,6 +38,33 @@ describe("Option `delimiter_auto`", function () {
     ]);
   });
 
+  it("sync custom score", function () {
+    // The default score elects `;` because it is more preferred than `:`
+    parse_sync("a:b;c\nd:e;f", {
+      delimiter_auto: true,
+    }).should.eql([
+      ["a:b", "c"],
+      ["d:e", "f"],
+    ]);
+    // A custom score receives the candidate info and the normalized options
+    const char_codes: number[] = [];
+    parse_sync("a:b;c\nd:e;f", {
+      delimiter_auto: {
+        score: (info, options) => {
+          char_codes.push(info.char_code);
+          return info.char_code === ":".charCodeAt(0)
+            ? 100
+            : (info.total - info.std) *
+                (options.preferred[info.char_code] || 1);
+        },
+      },
+    }).should.eql([
+      ["a", "b;c"],
+      ["d", "e;f"],
+    ]);
+    char_codes.length.should.eql(127);
+  });
+
   it("stream smaller than size", function (next) {
     let content = "";
     for (let i = 0; i < 10; i++) {