feat(new-tool): json to csv converter

src/tools/json-to-csv/json-to-csv.service.test.ts

@@ -0,0 +1,89 @@
+import { describe, expect, it } from 'vitest';
+import { convertArrayToCsv, getHeaders } from './json-to-csv.service';
+
+describe('json-to-csv service', () => {
+  describe('getHeaders', () => {
+    it('extracts all the keys from the array of objects', () => {
+      expect(getHeaders({ array: [{ a: 1, b: 2 }, { a: 3, c: 4 }] })).toEqual(['a', 'b', 'c']);
+    });
+
+    it('returns an empty array if the array is empty', () => {
+      expect(getHeaders({ array: [] })).toEqual([]);
+    });
+  });
+
+  describe('convertArrayToCsv', () => {
+    it('converts an array of objects to a CSV string', () => {
+      const array = [
+        { a: 1, b: 2 },
+        { a: 3, b: 4 },
+
+      ];
+
+      expect(convertArrayToCsv({ array })).toMatchInlineSnapshot(`
+        "a,b
+        1,2
+        3,4"
+      `);
+    });
+
+    it('converts an array of objects with different keys to a CSV string', () => {
+      const array = [
+        { a: 1, b: 2 },
+        { a: 3, c: 4 },
+      ];
+
+      expect(convertArrayToCsv({ array })).toMatchInlineSnapshot(`
+        "a,b,c
+        1,2,
+        3,,4"
+      `);
+    });
+
+    it('when a value is null, it is converted to the string "null"', () => {
+      const array = [
+        { a: null, b: 2 },
+      ];
+
+      expect(convertArrayToCsv({ array })).toMatchInlineSnapshot(`
+        "a,b
+        null,2"
+      `);
+    });
+
+    it('when a value is undefined, it is converted to an empty string', () => {
+      const array = [
+        { a: undefined, b: 2 },
+        { b: 3 },
+      ];
+
+      expect(convertArrayToCsv({ array })).toMatchInlineSnapshot(`
+        "a,b
+        ,2
+        ,3"
+      `);
+    });
+
+    it('when a value contains a comma, it is wrapped in double quotes', () => {
+      const array = [
+        { a: 'hello, world', b: 2 },
+      ];
+
+      expect(convertArrayToCsv({ array })).toMatchInlineSnapshot(`
+        "a,b
+        \\"hello, world\\",2"
+      `);
+    });
+
+    it('when a value contains a double quote, it is escaped with another double quote', () => {
+      const array = [
+        { a: 'hello "world"', b: 2 },
+      ];
+
+      expect(convertArrayToCsv({ array })).toMatchInlineSnapshot(`
+        "a,b
+        hello \\\\\\"world\\\\\\",2"
+      `);
+    });
+  });
+});