Math.max starts from -Infinity and Math.min from +Infinity

src/lib.ts

@@ -1550,8 +1550,15 @@ export static class Math {
      * @param values Numeric expressions to be evaluated.
      */
     public max(...values: number[]): number {
-        let m = Number.MIN_VALUE;
-        for (const v of values) if (v > m) m = v;
+        // -Infinity, not Number.MIN_VALUE: that is the smallest positive number, so the maximum of
+        // negative numbers came out as it. With no arguments the result is -Infinity, and any NaN
+        // makes it NaN.
+        let m = Number.NEGATIVE_INFINITY;
+        for (const v of values) {
+            if (isNaN(v)) return Number.NaN;
+            if (v > m) m = v;
+        }
+
         return m;
     }
 
@@ -1560,8 +1567,13 @@ export static class Math {
      * @param values Numeric expressions to be evaluated.
      */
     public min(...values: number[]): number {
-        let m = Number.MAX_VALUE;
-        for (const v of values) if (v < m) m = v;
+        // +Infinity, not Number.MAX_VALUE, so that Math.min() and Math.min(Infinity) are Infinity
+        let m = Number.POSITIVE_INFINITY;
+        for (const v of values) {
+            if (isNaN(v)) return Number.NaN;
+            if (v < m) m = v;
+        }
+
         return m;
     }
 

tests/math_max_min.ts

@@ -0,0 +1,22 @@
+// Math.max started from Number.MIN_VALUE, the smallest positive number, so the maximum of negative
+// numbers was 2.2e-308. Checked with typed comparisons rather than an `any` helper, so the test
+// does not depend on how `any` values compare.
+
+function main() {
+    const m = Math.max(-3, -5);
+    assert(m == -3, "Math.max(-3, -5)");
+    assert(Math.max(-1, -7) == -1, "Math.max(-1, -7)");
+    assert(Math.max(-2.5) == -2.5, "Math.max(-2.5)");
+    assert(Math.max(1, 7) == 7, "Math.max(1, 7)");
+    assert(Math.max() == Number.NEGATIVE_INFINITY, "Math.max()");
+    assert(Math.max(Number.NEGATIVE_INFINITY, -1e308) == -1e308, "Math.max(-Infinity, -1e308)");
+    assert(isNaN(Math.max(1, Number.NaN, 3)), "Math.max(1, NaN, 3)");
+
+    assert(Math.min(3, 5) == 3, "Math.min(3, 5)");
+    assert(Math.min(-1, -7) == -7, "Math.min(-1, -7)");
+    assert(Math.min() == Number.POSITIVE_INFINITY, "Math.min()");
+    assert(Math.min(Number.POSITIVE_INFINITY) == Number.POSITIVE_INFINITY, "Math.min(Infinity)");
+    assert(isNaN(Math.min(Number.NaN, 1)), "Math.min(NaN, 1)");
+
+    print("ALL DONE");
+}