feat(modifier): add number pre modifier

_e2e/expect_test.ts

@@ -7,6 +7,7 @@ import {
   fn,
   jestExtendedMatcherMap,
   not,
+  number,
   resolves,
   string,
   test,
@@ -1229,3 +1230,17 @@ test("passes when stringified value to be", async () => {
     "test",
   );
 });
+
+test("passes when numberized value to be", () => {
+  const expect = defineExpect({
+    matcherMap: {
+      toBe,
+    },
+    modifierMap: {
+      number,
+    },
+  });
+
+  expect("").number.toBe(0);
+  expect("test").number.toBe(NaN);
+});

mod.ts

@@ -120,6 +120,7 @@ export { resolves } from "./modifier/resolves.ts";
 export { trim } from "./modifier/trim.ts";
 export { debug } from "./modifier/debug.ts";
 export { string } from "./modifier/string.ts";
+export * from "./modifier/number.ts";
 export * from "./modifier/preset.ts";
 
 export * from "./modifier/types.ts";

modifier/README.md

@@ -31,7 +31,10 @@ import type { PreModifierContext } from "https://deno.land/x/unitest@$VERSION/mo
 
 type PreModifier = {
   type: "pre";
-  fn: (actual: unknown, context: PreModifierContext) => { actual: unknown };
+  fn: (
+    actual: unknown,
+    context: PreModifierContext,
+  ) => { actual: unknown } | Promise<{ actual: unknown }>;
 };
 ```
 
@@ -130,6 +133,34 @@ test("passes when stringified value to be", () => {
 });
 ```
 
+### number
+
+Use `.number` to convert any `actual` to `number`. Internally, the `Number`
+constructor is used.
+
+```ts
+import {
+  defineExpect,
+  number,
+  test,
+  toBe,
+} from "https://deno.land/x/unitest@$VERSION/mod.ts";
+
+const expect = defineExpect({
+  matcherMap: {
+    toBe,
+  },
+  modifierMap: {
+    number,
+  },
+});
+
+test("passes when numberized value to be", () => {
+  expect("").number.toBe(0);
+  expect("test").number.toBe(NaN);
+});
+```
+
 ## post modifier
 
 Post modifier is an object that is executed after a match. It interrupts the

modifier/mod.ts

@@ -6,4 +6,5 @@ export { resolves } from "./resolves.ts";
 export { trim } from "./trim.ts";
 export { debug } from "./debug.ts";
 export * from "./string.ts";
+export * from "./number.ts";
 export * from "./preset.ts";

modifier/number.ts

@@ -0,0 +1,36 @@
+// Copyright 2021-Present the Unitest authors. All rights reserved. MIT license.
+// This module is browser compatible.
+
+import type { PreModifier } from "./types.ts";
+
+/** Use `.number` to convert any `actual` to `number`. Internally, the `Number`
+ * constructor is used.
+ * ```ts
+ * import {
+ *   defineExpect,
+ *   number,
+ *   test,
+ *   toBe,
+ * } from "https://deno.land/x/unitest@$VERSION/mod.ts";
+ *
+ * const expect = defineExpect({
+ *   matcherMap: {
+ *     toBe,
+ *   },
+ *   modifierMap: {
+ *     number,
+ *   },
+ * });
+ *
+ * test("passes when numberized value to be", () => {
+ *   expect("").number.toBe(0);
+ *   expect("test").number.toBe(NaN);
+ * });
+ * ```
+ */
+const number: PreModifier<unknown, { actual: number }> = {
+  type: "pre",
+  fn: (actual) => ({ actual: Number(actual) }),
+};
+
+export { number };

modifier/number_test.ts

@@ -0,0 +1,14 @@
+// Copyright 2021-Present the Unitest authors. All rights reserved. MIT license.
+
+import { number } from "./number.ts";
+import { assertEquals } from "../dev_deps.ts";
+import type { PreModifierContext } from "./types.ts";
+
+Deno.test("number", () => {
+  const context = {} as PreModifierContext;
+  assertEquals(number.type, "pre");
+  assertEquals(number.fn("", context), { actual: 0 });
+  assertEquals(number.fn("test", context), { actual: NaN });
+  assertEquals(number.fn(1, context), { actual: 1 });
+  assertEquals(number.fn(1n, context), { actual: 1 });
+});