Merge pull request #105 from mefechoel/main

Add a Map.has reset with the same semantics as Set.has

package.json

@@ -58,6 +58,11 @@
       "import": "./dist/set-has.mjs",
       "default": "./dist/set-has.js"
     },
+    "./map-has": {
+      "types": "./dist/map-has.d.ts",
+      "import": "./dist/map-has.mjs",
+      "default": "./dist/map-has.js"
+    },
     "./utils": {
       "types": "./dist/utils.d.ts",
       "import": "./dist/utils.mjs",

readme.md

@@ -217,6 +217,35 @@ const userSet = new Set(["matt", "sofia", "waqas"] as const);
 userSet.has("bryan");
 ```
 
+### Make `Map.has()` less strict
+
+```ts
+import "@total-typescript/ts-reset/map-has";
+```
+
+Similar to `.includes` or `Set.has()`, `Map.has()` doesn't let you pass members that don't exist in the map's keys:
+
+```ts
+// BEFORE
+const userMap = new Map([["matt", 0], ["sofia", 1], [2, "waqas"]] as const);
+
+// Argument of type '"bryan"' is not assignable to
+// parameter of type '"matt" | "sofia" | "waqas"'.
+userMap.has("bryan");
+```
+
+With the rule enabled, `Map` is much smarter:
+
+```ts
+// AFTER
+import "@total-typescript/ts-reset/map-has";
+
+const userMap = new Map([["matt", 0], ["sofia", 1], [2, "waqas"]] as const);
+
+// .has now takes a string as the argument!
+userMap.has("bryan");
+```
+
 ### Removing `any[]` from `Array.isArray()`
 
 ```ts

src/entrypoints/map-has.d.ts

@@ -0,0 +1,9 @@
+/// <reference path="utils.d.ts" />
+
+interface Map<K, V> {
+  has(value: K | (TSReset.WidenLiteral<K> & {})): boolean;
+}
+
+interface ReadonlyMap<K, V> {
+  has(value: K | (TSReset.WidenLiteral<K> & {})): boolean;
+}

src/entrypoints/recommended.d.ts

@@ -4,3 +4,4 @@
 /// <reference path="json-parse.d.ts" />
 /// <reference path="array-includes.d.ts" />
 /// <reference path="set-has.d.ts" />
+/// <reference path="map-has.d.ts" />

src/tests/map-has.ts

@@ -0,0 +1,41 @@
+import { doNotExecute } from "./utils";
+
+doNotExecute(() => {
+  const map = new Map([
+    [1, "1"],
+    [2, "2"],
+    [3, "3"],
+  ] as const);
+
+  map.has(4);
+
+  map.has(
+    // @ts-expect-error
+    "4",
+  );
+
+  map.has(
+    // @ts-expect-error
+    true,
+  );
+});
+
+doNotExecute(() => {
+  const map = new Map([
+    [1, "1"],
+    [2, "2"],
+    [3, "3"],
+  ] as const) as ReadonlyMap<1 | 2 | 3, "1" | "2" | "3">;
+
+  map.has(4);
+
+  map.has(
+    // @ts-expect-error
+    "4",
+  );
+
+  map.has(
+    // @ts-expect-error
+    true,
+  );
+});