diff --git a/.changeset/olive-pets-exist.md b/.changeset/olive-pets-exist.md
new file mode 100644
index 0000000..f4a038f
--- /dev/null
+++ b/.changeset/olive-pets-exist.md
@@ -0,0 +1,38 @@
+---
+"@total-typescript/ts-reset": minor
+---
+
+author: @mefechoel
+
+Added the `Map.has` rule.
+
+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` follows the same semantics as `Set`.
+
+```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");
+```
diff --git a/readme.md b/readme.md
index 874aca8..a64e6d9 100644
--- a/readme.md
+++ b/readme.md
@@ -227,20 +227,28 @@ Similar to `.includes` or `Set.has()`, `Map.has()` doesn't let you pass members
 
 ```ts
 // BEFORE
-const userMap = new Map([["matt", 0], ["sofia", 1], [2, "waqas"]] as const);
+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:
+With the rule enabled, `Map` follows the same semantics as `Set`.
 
 ```ts
 // AFTER
 import "@total-typescript/ts-reset/map-has";
 
-const userMap = new Map([["matt", 0], ["sofia", 1], [2, "waqas"]] as const);
+const userMap = new Map([
+  ["matt", 0],
+  ["sofia", 1],
+  [2, "waqas"],
+] as const);
 
 // .has now takes a string as the argument!
 userMap.has("bryan");