1 files changed, 124 insertions, 0 deletions
diff --git a/js/console.ts b/js/console.ts
new file mode 100644
index 000000000..af92c8871
--- /dev/null
+++ b/js/console.ts
@@ -0,0 +1,124 @@
+const print = V8Worker2.print;
+
+// tslint:disable-next-line:no-any
+type ConsoleContext = Set<any>;
+
+// tslint:disable-next-line:no-any
+function getClassInstanceName(instance: any): string {
+  if (typeof instance !== "object") {
+    return "";
+  }
+  if (instance && instance.__proto__ && instance.__proto__.constructor) {
+    return instance.__proto__.constructor.name; // could be "Object" or "Array"
+  }
+  return "";
+}
+
+// tslint:disable-next-line:no-any
+function stringify(ctx: ConsoleContext, value: any): string {
+  switch (typeof value) {
+    case "string":
+      return value;
+    case "number":
+    case "boolean":
+    case "undefined":
+    case "symbol":
+      return String(value);
+    case "function":
+      if (value.name && value.name !== "anonymous") {
+        // from MDN spec
+        return `[Function: ${value.name}]`;
+      }
+      return "[Function]";
+    case "object":
+      if (value === null) {
+        return "null";
+      }
+
+      if (ctx.has(value)) {
+        return "[Circular]";
+      }
+
+      ctx.add(value);
+      const entries: string[] = [];
+
+      if (Array.isArray(value)) {
+        for (const el of value) {
+          entries.push(stringify(ctx, el));
+        }
+
+        ctx.delete(value);
+
+        if (entries.length === 0) {
+          return "[]";
+        }
+        return `[ ${entries.join(", ")} ]`;
+      } else {
+        let baseString = "";
+
+        const className = getClassInstanceName(value);
+        let shouldShowClassName = false;
+        if (className && className !== "Object" && className !== "anonymous") {
+          shouldShowClassName = true;
+        }
+
+        for (const key of Object.keys(value)) {
+          entries.push(`${key}: ${stringify(ctx, value[key])}`);
+        }
+
+        ctx.delete(value);
+
+        if (entries.length === 0) {
+          baseString = "{}";
+        } else {
+          baseString = `{ ${entries.join(", ")} }`;
+        }
+
+        if (shouldShowClassName) {
+          baseString = `${className} ${baseString}`;
+        }
+
+        return baseString;
+      }
+    default:
+      return "[Not Implemented]";
+  }
+}
+
+// tslint:disable-next-line:no-any
+function stringifyArgs(args: any[]): string {
+  const out: string[] = [];
+  for (const a of args) {
+    if (typeof a === "string") {
+      out.push(a);
+    } else {
+      // tslint:disable-next-line:no-any
+      out.push(stringify(new Set<any>(), a));
+    }
+  }
+  return out.join(" ");
+}
+
+export class Console {
+  // tslint:disable-next-line:no-any
+  log(...args: any[]): void {
+    print(stringifyArgs(args));
+  }
+
+  debug = this.log;
+  info = this.log;
+
+  // tslint:disable-next-line:no-any
+  warn(...args: any[]): void {
+    print(`ERROR: ${stringifyArgs(args)}`);
+  }
+
+  error = this.warn;
+
+  // tslint:disable-next-line:no-any
+  assert(condition: boolean, ...args: any[]): void {
+    if (!condition) {
+      throw new Error(`Assertion failed: ${stringifyArgs(args)}`);
+    }
+  }
+}