LibJS: Implement console.assert()

Userland/Applications/Browser/BrowserConsoleClient.cpp

@@ -124,4 +124,25 @@ JS::Value BrowserConsoleClient::count_reset()
     return JS::js_undefined();
 }
 
+JS::Value BrowserConsoleClient::assert_()
+{
+    auto& vm = this->vm();
+    if (!vm.argument(0).to_boolean()) {
+        StringBuilder html;
+        if (vm.argument_count() > 1) {
+            html.append("<span class=\"error\">");
+            html.append("Assertion failed:");
+            html.append("</span>");
+            html.append(" ");
+            html.append(escape_html_entities(vm.join_arguments(1)));
+        } else {
+            html.append("<span class=\"error\">");
+            html.append("Assertion failed");
+            html.append("</span>");
+        }
+        m_console_widget.print_html(html.string_view());
+    }
+    return JS::js_undefined();
+}
+
 }

Userland/Applications/Browser/BrowserConsoleClient.h

@@ -53,6 +53,7 @@ private:
     virtual JS::Value trace() override;
     virtual JS::Value count() override;
     virtual JS::Value count_reset() override;
+    virtual JS::Value assert_() override;
 
     ConsoleWidget& m_console_widget;
 };

Userland/Libraries/LibJS/Console.cpp

@@ -1,6 +1,6 @@
 /*
  * Copyright (c) 2020, Emanuele Torre <torreemanuele6@gmail.com>
- * Copyright (c) 2020, Linus Groh <mail@linusgroh.de>
+ * Copyright (c) 2020-2021, Linus Groh <mail@linusgroh.de>
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
@@ -118,6 +118,13 @@ Value Console::count_reset()
     return js_undefined();
 }
 
+Value Console::assert_()
+{
+    if (m_client)
+        return m_client->assert_();
+    return js_undefined();
+}
+
 unsigned Console::counter_increment(String label)
 {
     auto value = m_counters.get(label);

Userland/Libraries/LibJS/Console.h

@@ -57,13 +57,11 @@ public:
     Value info();
     Value log();
     Value warn();
-
     Value clear();
-
     Value trace();
-
     Value count();
     Value count_reset();
+    Value assert_();
 
     unsigned counter_increment(String label);
     bool counter_reset(String label);
@@ -77,7 +75,7 @@ private:
 
 class ConsoleClient {
 public:
-    ConsoleClient(Console& console)
+    explicit ConsoleClient(Console& console)
         : m_console(console)
     {
     }
@@ -91,6 +89,7 @@ public:
     virtual Value trace() = 0;
     virtual Value count() = 0;
     virtual Value count_reset() = 0;
+    virtual Value assert_() = 0;
 
 protected:
     virtual ~ConsoleClient() = default;

Userland/Libraries/LibJS/Runtime/CommonPropertyNames.h

@@ -71,6 +71,7 @@ namespace JS {
     P(asUintN)                               \
     P(asin)                                  \
     P(asinh)                                 \
+    P(assert)                                \
     P(at)                                    \
     P(atan)                                  \
     P(atan2)                                 \

Userland/Libraries/LibJS/Runtime/ConsoleObject.cpp

@@ -1,6 +1,6 @@
 /*
  * Copyright (c) 2020, Andreas Kling <kling@serenityos.org>
- * Copyright (c) 2020, Linus Groh <mail@linusgroh.de>
+ * Copyright (c) 2020-2021, Linus Groh <mail@linusgroh.de>
  * Copyright (c) 2020, Emanuele Torre <torreemanuele6@gmail.com>
  * All rights reserved.
  *
@@ -50,6 +50,7 @@ void ConsoleObject::initialize(GlobalObject& global_object)
     define_native_function(vm.names.count, count);
     define_native_function(vm.names.countReset, count_reset);
     define_native_function(vm.names.clear, clear);
+    define_native_function(vm.names.assert, assert_);
 }
 
 ConsoleObject::~ConsoleObject()
@@ -101,4 +102,9 @@ JS_DEFINE_NATIVE_FUNCTION(ConsoleObject::clear)
     return global_object.console().clear();
 }
 
+JS_DEFINE_NATIVE_FUNCTION(ConsoleObject::assert_)
+{
+    return global_object.console().assert_();
+}
+
 }

Userland/Libraries/LibJS/Runtime/ConsoleObject.h

@@ -48,6 +48,7 @@ private:
     JS_DECLARE_NATIVE_FUNCTION(count);
     JS_DECLARE_NATIVE_FUNCTION(count_reset);
     JS_DECLARE_NATIVE_FUNCTION(clear);
+    JS_DECLARE_NATIVE_FUNCTION(assert_);
 };
 
 }

Userland/Libraries/LibJS/Runtime/VM.cpp

@@ -321,10 +321,10 @@ void VM::throw_exception(Exception& exception)
     unwind(ScopeType::Try);
 }
 
-String VM::join_arguments() const
+String VM::join_arguments(size_t start_index) const
 {
     StringBuilder joined_arguments;
-    for (size_t i = 0; i < argument_count(); ++i) {
+    for (size_t i = start_index; i < argument_count(); ++i) {
         joined_arguments.append(argument(i).to_string_without_side_effects().characters());
         if (i != argument_count() - 1)
             joined_arguments.append(' ');

Userland/Libraries/LibJS/Runtime/VM.h

@@ -222,7 +222,7 @@ public:
 
     Value construct(Function&, Function& new_target, Optional<MarkedValueList> arguments, GlobalObject&);
 
-    String join_arguments() const;
+    String join_arguments(size_t start_index = 0) const;
 
     Value resolve_this_binding(GlobalObject&) const;
     const ScopeObject* find_this_scope() const;

Userland/Services/WebContent/WebContentConsoleClient.cpp

@@ -168,4 +168,25 @@ JS::Value WebContentConsoleClient::count_reset()
     return JS::js_undefined();
 }
 
+JS::Value WebContentConsoleClient::assert_()
+{
+    auto& vm = this->vm();
+    if (!vm.argument(0).to_boolean()) {
+        StringBuilder html;
+        if (vm.argument_count() > 1) {
+            html.append("<span class=\"error\">");
+            html.append("Assertion failed:");
+            html.append("</span>");
+            html.append(" ");
+            html.append(escape_html_entities(vm.join_arguments(1)));
+        } else {
+            html.append("<span class=\"error\">");
+            html.append("Assertion failed");
+            html.append("</span>");
+        }
+        print_html(html.string_view());
+    }
+    return JS::js_undefined();
+}
+
 }

Userland/Services/WebContent/WebContentConsoleClient.h

@@ -56,6 +56,7 @@ private:
     virtual JS::Value trace() override;
     virtual JS::Value count() override;
     virtual JS::Value count_reset() override;
+    virtual JS::Value assert_() override;
 
     ClientConnection& m_client;
     WeakPtr<JS::Interpreter> m_interpreter;

Userland/Utilities/js.cpp

@@ -650,32 +650,38 @@ public:
         outln("{}", vm().join_arguments());
         return JS::js_undefined();
     }
+
     virtual JS::Value info() override
     {
         outln("(i) {}", vm().join_arguments());
         return JS::js_undefined();
     }
+
     virtual JS::Value debug() override
     {
         outln("\033[36;1m{}\033[0m", vm().join_arguments());
         return JS::js_undefined();
     }
+
     virtual JS::Value warn() override
     {
         outln("\033[33;1m{}\033[0m", vm().join_arguments());
         return JS::js_undefined();
     }
+
     virtual JS::Value error() override
     {
         outln("\033[31;1m{}\033[0m", vm().join_arguments());
         return JS::js_undefined();
     }
+
     virtual JS::Value clear() override
     {
         out("\033[3J\033[H\033[2J");
         fflush(stdout);
         return JS::js_undefined();
     }
+
     virtual JS::Value trace() override
     {
         outln("{}", vm().join_arguments());
@@ -687,6 +693,7 @@ public:
         }
         return JS::js_undefined();
     }
+
     virtual JS::Value count() override
     {
         auto label = vm().argument_count() ? vm().argument(0).to_string_without_side_effects() : "default";
@@ -694,6 +701,7 @@ public:
         outln("{}: {}", label, counter_value);
         return JS::js_undefined();
     }
+
     virtual JS::Value count_reset() override
     {
         auto label = vm().argument_count() ? vm().argument(0).to_string_without_side_effects() : "default";
@@ -703,6 +711,20 @@ public:
             outln("\033[33;1m\"{}\" doesn't have a count\033[0m", label);
         return JS::js_undefined();
     }
+
+    virtual JS::Value assert_() override
+    {
+        auto& vm = this->vm();
+        if (!vm.argument(0).to_boolean()) {
+            if (vm.argument_count() > 1) {
+                out("\033[31;1mAssertion failed:\033[0m");
+                outln(" {}", vm.join_arguments(1));
+            } else {
+                outln("\033[31;1mAssertion failed\033[0m");
+            }
+        }
+        return JS::js_undefined();
+    }
 };
 
 int main(int argc, char** argv)