fix: add array of arrays type (#75)

cypress/e2e/array-of-arrays.cy.ts

@@ -1,14 +1,15 @@
 import '../../src'
 
-// https://github.com/bahmutov/cypress-each/issues/2
 describe('Array of arrays', () => {
   it.each([
-    [1, 'foo'],
-    [2, 'bar'],
-  ])('test with %d %s', (a, b) => {
+    [1, 'foo', true],
+    [2, 'bar', false],
+  ])('test with %d %s', (a: number, b: string, c: boolean) => {
     // a should be a number
     // b should be a string
+    // b should be a boolean
     expect(a, 'first argument').to.be.a('number')
     expect(b, 'second argument').to.be.a('string')
+    expect(c, 'third argument').to.be.a('boolean')
   })
 })

package.json

@@ -8,7 +8,7 @@
     "src"
   ],
   "scripts": {
-    "lint": "tsc --pretty --allowJs --strict --noEmit src/index.js cypress/**/*.js cypress/**/*.ts",
+    "lint": "tsc --pretty --allowJs --strict --noEmit src/index.js cypress/**/*.ts",
     "test": "cypress-expect run --expect cypress/expected.json",
     "semantic-release": "semantic-release"
   },

src/index.d.ts

@@ -18,7 +18,13 @@ type TestCaseObject<T> = {
 }
 
 declare namespace Mocha {
-  type TestCallback<T> = (this: Context, arg0: T, arg1: any, arg2: any) => void
+  type TestCallback<T extends readonly any[]> = T extends []
+    ? (this: Context, arg1: any, arg2: any) => void
+    : Parameters<(...res: [...T, any, any]) => void> extends [...infer R]
+    ? R extends readonly [...T, any, any]
+      ? (this: Context, ...res: [...R]) => void
+      : never
+    : never
   type TestCallback1<T0> = (this: Context, arg0: T0) => void
   type TestCallback2<T0, T1> = (this: Context, arg0: T0, arg1: T1) => void
   type TestCallback3<T0, T1, T2> = (
@@ -38,11 +44,19 @@ declare namespace Mocha {
      * @example it.each([1, 2, 3])('test %K', (x) => ...)
      * @see https://github.com/bahmutov/cypress-each
      */
+    each<T extends readonly [...T]>(
+      values: Array<readonly [...T]>,
+      totalChunks?: number,
+      chunkIndex?: number,
+    ): (
+      titlePattern: string | TestTitleFn<[...T]>,
+      fn: TestCallback<[...T]>,
+    ) => void
     each<T = unknown>(
       values: T[] | number,
       totalChunks?: number | ItemPredicateFunction<T>,
       chunkIndex?: number,
-    ): (titlePattern: string | TestTitleFn<T>, fn: TestCallback<T>) => void
+    ): (titlePattern: string | TestTitleFn<T>, fn: TestCallback<[T]>) => void
 
     /**
      * A single test case object where the keys are test titles,
@@ -104,8 +118,8 @@ declare namespace Mocha {
      */
     each<T = unknown>(
       values: T[] | number,
-      totalChunks?: number,
+      totalChunks?: number | ItemPredicateFunction<T>,
       chunkIndex?: number,
-    ): (titlePattern: string | TestTitleFn<T>, fn: TestCallback<T>) => void
+    ): (titlePattern: string | TestTitleFn<T>, fn: TestCallback<[T]>) => void
   }
 }