From efb08e4a136df446ee15f68d0051bdeeed273d57 Mon Sep 17 00:00:00 2001
From: PopGoesTheWza <PopGoesTheWza@gmail.com>
Date: Tue, 7 Sep 2021 10:54:53 +0200
Subject: [PATCH] feat: `is.propertyKey`

---
 source/index.ts | 5 +++++
 test/test.ts    | 7 +++++++
 2 files changed, 12 insertions(+)

diff --git a/source/index.ts b/source/index.ts
index d9fb699..ef2ac3f 100644
--- a/source/index.ts
+++ b/source/index.ts
@@ -150,6 +150,8 @@ is.string = isOfType<string>('string');
 const isNumberType = isOfType<number>('number');
 is.number = (value: unknown): value is number => isNumberType(value) && !is.nan(value);
 
+is.propertyKey = (value: unknown): value is PropertyKey => is.any([is.string, is.number, is.symbol], value);
+
 is.bigint = isOfType<bigint>('bigint');
 
 // eslint-disable-next-line @typescript-eslint/ban-types
@@ -448,6 +450,7 @@ interface Assert {
 	undefined: (value: unknown) => asserts value is undefined;
 	string: (value: unknown) => asserts value is string;
 	number: (value: unknown) => asserts value is number;
+	propertyKey: (value: unknown) => asserts value is PropertyKey;
 	bigint: (value: unknown) => asserts value is bigint;
 	// eslint-disable-next-line @typescript-eslint/ban-types
 	function_: (value: unknown) => asserts value is Function;
@@ -538,6 +541,8 @@ export const assert: Assert = {
 	undefined: (value: unknown): asserts value is undefined => assertType(is.undefined(value), 'undefined', value),
 	string: (value: unknown): asserts value is string => assertType(is.string(value), 'string', value),
 	number: (value: unknown): asserts value is number => assertType(is.number(value), 'number', value),
+	// ? Is an AssertionTypeDescription.propertyKey entry necessary?
+	propertyKey: (value: unknown): asserts value is number => assertType(is.propertyKey(value), 'PropertyKey', value),
 	bigint: (value: unknown): asserts value is bigint => assertType(is.bigint(value), 'bigint', value),
 	// eslint-disable-next-line @typescript-eslint/ban-types
 	function_: (value: unknown): asserts value is Function => assertType(is.function_(value), 'Function', value),
diff --git a/test/test.ts b/test/test.ts
index 30c1a86..69b2b41 100644
--- a/test/test.ts
+++ b/test/test.ts
@@ -613,6 +613,13 @@ test('is.number', t => {
 	testType(t, 'number', ['integer', 'safeInteger', 'infinite']);
 });
 
+test('is.propertyKey', t => {
+	// ??? Unsure what is the correct syntax to `testType` multiple types. Also are the exclusion relevant?
+	testType(t, 'string', ['emptyString', 'numericString']);
+	testType(t, 'number', ['nan', 'integer', 'safeInteger', 'infinite']);
+	testType(t, 'symbol');
+});
+
 test('is.bigint', t => {
 	testType(t, 'bigint');
 });