From a6a78f160e996d837a17896562af1017eb6fde25 Mon Sep 17 00:00:00 2001
From: EuAndreh <eu@euandre.org>
Date: Fri, 11 Jul 2025 14:45:07 -0300
Subject: src/sjs.mjs: Add isNumeric()

---
 src/sjs.mjs   |  4 ++++
 tests/sjs.mjs | 15 +++++++++++++++
 2 files changed, 19 insertions(+)

diff --git a/src/sjs.mjs b/src/sjs.mjs
index 0b2c705..2c9d551 100644
--- a/src/sjs.mjs
+++ b/src/sjs.mjs
@@ -1,6 +1,10 @@
 export const max = (a, b) => a > b ? a : b;
 export const min = (a, b) => a < b ? a : b;
 
+export const isNumeric = c =>
+	c.charCodeAt(0) >= "0".charCodeAt(0) &&
+	c.charCodeAt(0) <= "9".charCodeAt(0);
+
 export const explode = s => s.split("");
 
 export const getIn = (obj, path) =>
diff --git a/tests/sjs.mjs b/tests/sjs.mjs
index dbcd635..c8f52dd 100644
--- a/tests/sjs.mjs
+++ b/tests/sjs.mjs
@@ -1,6 +1,7 @@
 import {
 	max,
 	min,
+	isNumeric,
 	explode,
 	getIn,
 	merge,
@@ -58,6 +59,19 @@ const test_min = t => {
 	});
 };
 
+const test_isNumeric = t => {
+	t.start("isNumeric()");
+
+	t.testing("checks if (first) char is numeric", () => {
+		t.assertEq(isNumeric("0"), true);
+		t.assertEq(isNumeric("5"), true);
+		t.assertEq(isNumeric("9"), true);
+		t.assertEq(isNumeric("10"), true);
+		t.assertEq(isNumeric("1a"), true);
+		t.assertEq(isNumeric("a1"), false);
+	});
+};
+
 const test_explode = t => {
 	t.start("explode()");
 
@@ -976,6 +990,7 @@ const test_repeat = t => {
 runTests([
 	test_max,
 	test_min,
+	test_isNumeric,
 	test_explode,
 	test_getIn,
 	test_merge,
-- 
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