Add Object.is (#836)

Author: MaxGraey

std/assembly/index.d.ts

@@ -1541,6 +1541,11 @@ declare class Date {
   setTime(value: i64): i64;
 }
 
+declare class Object {
+  /** The Object.is() method determines whether two values are the same value. */
+  static is<T>(value1: T, value2: T): bool;
+}
+
 /** Environmental tracing function for debugging purposes. */
 declare function trace(msg: string, n?: i32, a0?: f64, a1?: f64, a2?: f64, a3?: f64, a4?: f64): void;
 

std/assembly/object.ts

@@ -0,0 +1,21 @@
+export class Object {
+  static is<T>(value1: T, value2: T): bool {
+    if (isFloat<T>()) {
+      if (value1 == value2) {
+        // 0 === -0, but they are not identical
+        if (sizeof<T>() == 8) {
+          // @ts-ignore: typecast
+          return reinterpret<u64>(value1) == reinterpret<u64>(value2);
+        } else {
+          // @ts-ignore: typecast
+          return reinterpret<u32>(value1) == reinterpret<u32>(value2);
+        }
+      }
+      // NaN !== NaN, but they are identical.
+      // @ts-ignore: typecast
+      return bool(i32(isNaN(value1)) & i32(isNaN(value2)));
+    }
+    // For references, strings, integers and booleans
+    return value1 == value2;
+  }
+}

tests/compiler/std/object.json

@@ -0,0 +1,5 @@
+{
+  "asc_flags": [
+    "--runtime none"
+  ]
+}