From db537093e043e97eb19e0fa4c497bf842a6e2bbb Mon Sep 17 00:00:00 2001
From: David Worms <david@adaltas.com>
Date: Fri, 15 Mar 2024 11:37:58 +0100
Subject: [PATCH] test(csv-stringify): columns type test as const

---
 packages/csv-stringify/dist/cjs/index.d.cts   | 2 +-
 packages/csv-stringify/dist/esm/index.d.ts    | 2 +-
 packages/csv-stringify/test/api.types.sync.ts | 2 +-
 packages/csv-stringify/test/api.types.ts      | 7 +++++++
 4 files changed, 10 insertions(+), 3 deletions(-)

diff --git a/packages/csv-stringify/dist/cjs/index.d.cts b/packages/csv-stringify/dist/cjs/index.d.cts
index 4c28ef9e4..618b7ee6b 100644
--- a/packages/csv-stringify/dist/cjs/index.d.cts
+++ b/packages/csv-stringify/dist/cjs/index.d.cts
@@ -61,7 +61,7 @@ export interface Options extends stream.TransformOptions {
      * can refer to nested properties of the input JSON
      * see the "header" option on how to print columns names on the first line
      */
-    columns?: string[] | PlainObject<string> | ColumnOption[]
+    columns?: readonly string[] | PlainObject<string> | readonly ColumnOption[]
     /**
      * Set the field delimiter, one character only, defaults to a comma.
      */
diff --git a/packages/csv-stringify/dist/esm/index.d.ts b/packages/csv-stringify/dist/esm/index.d.ts
index 4c28ef9e4..618b7ee6b 100644
--- a/packages/csv-stringify/dist/esm/index.d.ts
+++ b/packages/csv-stringify/dist/esm/index.d.ts
@@ -61,7 +61,7 @@ export interface Options extends stream.TransformOptions {
      * can refer to nested properties of the input JSON
      * see the "header" option on how to print columns names on the first line
      */
-    columns?: string[] | PlainObject<string> | ColumnOption[]
+    columns?: readonly string[] | PlainObject<string> | readonly ColumnOption[]
     /**
      * Set the field delimiter, one character only, defaults to a comma.
      */
diff --git a/packages/csv-stringify/test/api.types.sync.ts b/packages/csv-stringify/test/api.types.sync.ts
index e2ba3761c..07dc3c6b3 100644
--- a/packages/csv-stringify/test/api.types.sync.ts
+++ b/packages/csv-stringify/test/api.types.sync.ts
@@ -20,7 +20,7 @@ describe('API Types', () => {
       const rd: RecordDelimiter | undefined = options.record_delimiter
       const cast = options.cast
       const castBoolean : Cast<boolean> | undefined = cast?.boolean
-      const columns: string[] | PlainObject<string> | ColumnOption[] | undefined = options.columns
+      const columns: readonly string[] | PlainObject<string> | readonly ColumnOption[] | undefined = options.columns
       return [
         rd, castBoolean, columns
       ]
diff --git a/packages/csv-stringify/test/api.types.ts b/packages/csv-stringify/test/api.types.ts
index 2a11182c4..9907e65ef 100644
--- a/packages/csv-stringify/test/api.types.ts
+++ b/packages/csv-stringify/test/api.types.ts
@@ -1,6 +1,7 @@
 
 import 'should'
 import { stringify, CastingContext, Options, Stringifier } from '../lib/index.js'
+import { stringify as stringifySync } from '../lib/index.js'
 
 describe('API Types', () => {
   
@@ -74,6 +75,12 @@ describe('API Types', () => {
         field3: 'column3'
       }
     })
+      
+    it("columns as const", () => {
+      const options: Options = {};
+      options.columns = ["b", "a"];
+      options.columns = ["b", "a"] as const;
+    });
     
     it('delimiter', () => {
       const options: Options = {}