diff --git a/README.md b/README.md
index d3f59fb..13f75f7 100644
--- a/README.md
+++ b/README.md
@@ -129,7 +129,9 @@ Issues can be funded by anyone and the money will be transparently distributed t
 
 ### `Primitive`
 
-Type representing primitive types in TypeScript: `number | boolean | string | symbol`
+Type representing primitive types in JavaScript, and thus TypeScript: `number | bigint | boolean | string | symbol`
+
+You can test for singular of these types with [`typeof`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/typeof)
 
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diff --git a/package.json b/package.json
index 51338d4..bedaffe 100644
--- a/package.json
+++ b/package.json
@@ -21,13 +21,13 @@
     "ci-check": "npm run prettier && npm run lint && npm run tsc && npm run test",
     "reinstall": "rm -rf node_modules/ dist/ && npm install",
     "prettier": "prettier --list-different 'src/**/*.ts' || (echo '\nPlease fix code formatting by running:\nnpm run prettier:fix\n'; exit 1)",
-    "prettier:fix": "prettier --write 'src/**/*.ts'",
-    "lint": "tslint --project './tsconfig.json'",
+    "prettier:fix": "prettier --write src/**/*.ts",
+    "lint": "tslint --project ./tsconfig.json",
     "tsc": "tsc -p . --noEmit",
     "tsc:watch": "tsc -p . --noEmit -w",
     "test": "jest --config jest.config.json",
     "test:watch": "jest --config jest.config.json --watch",
-    "test:update": "jest --config jest.config.json --no-cache -u && dts-jest-remap ./src/*.spec.ts --rename '{{basename}}.snap.{{extname}}'",
+    "test:update": "jest --config jest.config.json --no-cache -u && dts-jest-remap ./src/*.spec.ts --rename {{basename}}.snap.{{extname}}",
     "prebuild": "rm -rf dist/",
     "build": "tsc -p ./tsconfig.build.json --outDir dist/",
     "prepublishOnly": "npm run reinstall && npm run ci-check && npm run build"
diff --git a/src/mapped-types.ts b/src/mapped-types.ts
index e9d5736..864d001 100644
--- a/src/mapped-types.ts
+++ b/src/mapped-types.ts
@@ -5,14 +5,14 @@
 
 /**
  * Primitive
- * @desc Type representing primitive types in TypeScript: `number | boolean | string | symbol`
+ * @desc Type representing primitive types in TypeScript: `number | bigint | boolean | string | symbol`
  * @example
- *   type Various = number | boolean | string | symbol | object;
+ *   type Various = number | string | object;
  *
  *    // Expect: object
- *   Exclude<Various, Primitive>
+ *   type Cleaned = Exclude<Various, Primitive>
  */
-export type Primitive = number | boolean | string | symbol;
+export type Primitive = number | bigint | boolean | string | symbol;
 
 /**
  * Falsey