Number constants (#420)

Co-authored-by: HalidOdat <halidodat@gmail.com>

Author: Paul Lancaster

boa/src/builtins/number/mod.rs

@@ -402,7 +402,20 @@ impl Number {
         make_builtin_fn(Self::to_string, "toString", &prototype, 1);
         make_builtin_fn(Self::value_of, "valueOf", &prototype, 0);
 
-        make_constructor_fn("Number", 1, Self::make_number, global, prototype, true)
+        let number = make_constructor_fn("Number", 1, Self::make_number, global, prototype, true);
+
+        // Constants from:
+        // https://tc39.es/ecma262/#sec-properties-of-the-number-constructor
+        number.set_field("EPSILON", Value::from(std::f64::EPSILON));
+        number.set_field("MAX_SAFE_INTEGER", Value::from(9_007_199_254_740_991_f64));
+        number.set_field("MIN_SAFE_INTEGER", Value::from(-9_007_199_254_740_991_f64));
+        number.set_field("MAX_VALUE", Value::from(std::f64::MAX));
+        number.set_field("MIN_VALUE", Value::from(std::f64::MIN));
+        number.set_field("NEGATIVE_INFINITY", Value::from(f64::NEG_INFINITY));
+        number.set_field("POSITIVE_INFINITY", Value::from(f64::INFINITY));
+        number.set_field("NaN", Value::from(f64::NAN));
+
+        number
     }
 
     /// Initialise the `Number` object on the global object.

boa/src/builtins/number/tests.rs

@@ -442,3 +442,31 @@ fn from_bigint() {
     assert_eq!(&forward(&mut engine, "Number(100000n)"), "100000",);
     assert_eq!(&forward(&mut engine, "Number(1n << 1240n)"), "Infinity",);
 }
+
+#[test]
+fn number_constants() {
+    let realm = Realm::create();
+    let mut engine = Interpreter::new(realm);
+
+    assert!(!forward_val(&mut engine, "Number.EPSILON")
+        .unwrap()
+        .is_null_or_undefined());
+    assert!(!forward_val(&mut engine, "Number.MAX_SAFE_INTEGER")
+        .unwrap()
+        .is_null_or_undefined());
+    assert!(!forward_val(&mut engine, "Number.MIN_SAFE_INTEGER")
+        .unwrap()
+        .is_null_or_undefined());
+    assert!(!forward_val(&mut engine, "Number.MAX_VALUE")
+        .unwrap()
+        .is_null_or_undefined());
+    assert!(!forward_val(&mut engine, "Number.MIN_VALUE")
+        .unwrap()
+        .is_null_or_undefined());
+    assert!(!forward_val(&mut engine, "Number.NEGATIVE_INFINITY")
+        .unwrap()
+        .is_null_or_undefined());
+    assert!(!forward_val(&mut engine, "Number.POSITIVE_INFINITY")
+        .unwrap()
+        .is_null_or_undefined());
+}