feat(csv-generate): types column option defined as an udf (fix #417)

Author: wdavidw

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

@@ -11,11 +11,24 @@ export class Generator extends stream.Readable {
     readonly options: Options;
 }
 
+export type ColumnsFunctionArgs = {
+    options: Options;
+    state: State;
+};
+export type ColumnsFunction = (args: ColumnsFunctionArgs) => string;
+
+export type State = {
+    start_time: number,
+    fixed_size_buffer: number,
+    count_written: number,
+    count_created: number,
+}
+
 export interface Options extends stream.ReadableOptions {
     /**
      * Define the number of generated fields and the generation method.
      */
-    columns?: number | string[];
+    columns?: number | (string | ColumnsFunction)[];
     /**
      * Set the field delimiter.
      */

packages/csv-generate/test/api.types.ts

@@ -48,7 +48,12 @@ describe('API Types', () => {
     it('columns', () => {
       const options: Options = {}
       options.columns = 8
-      options.columns = ['ascii', 'bool', 'int']
+      options.columns = [
+        "ascii",
+        "bool",
+        "int",
+        ({ options, state }) => options.delimiter + "ok" + state.start_time,
+      ];
     })
 
     it('delimiter', () => {