diff --git a/README.md b/README.md
index d141757..2f901f8 100644
--- a/README.md
+++ b/README.md
@@ -9,6 +9,8 @@ An experimental tool to generate JavaScript code from Crystal code.
   * [Code Snippets](#javascript-code)
     * [`_call`](#_call)
     * [`async` / `await`](#async--await)
+    * [Strict Mode (opt-in)](#strict-mode-opt-in)
+  * [Browser API Wrappers](#browser-api-wrappers)
   * [Functions](#javascript-functions)
   * [Classes](#javascript-classes)
   * [Files](#javascript-files)
@@ -88,6 +90,62 @@ end
 puts MyAsyncSnippet.to_js
 ```
 
+#### Strict Mode (opt-in)
+
+You can enable strict mode per generated unit:
+
+- `JS::Code`: `def_to_js strict: true do ... end`
+- `JS::File`: `def_to_js strict: true do ... end`
+- `JS::Module`: `def_to_js strict: true do ... end`
+
+In strict mode:
+
+- Referencing/calling undeclared JS identifiers raises a compile-time error.
+- `_literal_js(...)` is rejected at compile-time.
+
+```crystal
+require "js"
+
+class MyStrictCode < JS::Code
+  def_to_js strict: true do
+    console.log("ready")
+  end
+end
+```
+
+### Browser API Wrappers
+
+In strict mode, method calls without an explicit receiver are resolved against a default browser context object.
+For now, this context exposes `console` with:
+
+- `log`
+- `info`
+- `warn`
+- `error`
+
+Use regular-looking calls (instead of wrapper constants or `_literal_js`):
+
+```crystal
+class MyConsoleCode < JS::Code
+  def_to_js strict: true do
+    console.log("Hello", 7, true)
+  end
+end
+```
+
+#### Adding wrappers iteratively
+
+Use this pattern for additional browser APIs:
+
+1. Add/update `JS::Context::Browser` with the new receiverless entrypoint (like `console`).
+2. Add a wrapper under `src/js/context/<api>.cr` in `JS::Context`.
+3. Inherit browser wrappers from `JS::Context::ContextObject`, which stores the current JS call chain and provides call-chain initialization.
+4. Return a typed browser context object from each wrapper method (for now, `console.log/info/warn/error` return `JS::Context::Undefined`).
+5. Add specs that:
+   - verify JS output from wrapper calls;
+   - verify typed return wrappers and their `to_js_ref` output;
+   - verify strict mode acceptance when wrappers are used.
+
 ### JavaScript Functions
 
 If you were wondering how to define a function within `JS::Code.def_to_js` - that's not possible. Well, technically it is via a `_literal_js` call but that's dirty and there is a better way:
diff --git a/spec/js/code/strict_mode_spec.cr b/spec/js/code/strict_mode_spec.cr
new file mode 100644
index 0000000..1eafdb8
--- /dev/null
+++ b/spec/js/code/strict_mode_spec.cr
@@ -0,0 +1,75 @@
+require "../../spec_helper"
+
+module JS::Code::StrictModeSpec
+  class StrictCode < JS::Code
+    js_alias "doc", "document"
+
+    def_to_js strict: true do
+      doc.querySelector("body")
+      console.info("ready")
+    end
+  end
+
+  class LooseCode < JS::Code
+    def_to_js do
+      undeclaredThing.callMe._call
+    end
+  end
+
+  describe "strict mode" do
+    it "allows declared externs and typed wrappers" do
+      expected = <<-JS.squish
+      document.querySelector("body");
+      console.info("ready");
+      JS
+
+      StrictCode.to_js.should eq(expected)
+    end
+
+    it "keeps loose mode backwards-compatible" do
+      expected = <<-JS.squish
+      undeclaredThing.callMe();
+      JS
+
+      LooseCode.to_js.should eq(expected)
+    end
+
+    it "fails on undeclared identifiers in strict mode" do
+      source = <<-CR
+      require "./src/js"
+
+      class StrictFailureCode < JS::Code
+        def_to_js strict: true do
+          missing_api._call
+        end
+      end
+
+      puts StrictFailureCode.to_js
+      CR
+
+      exit_code, _stdout, stderr = crystal_eval(source)
+      exit_code.should_not eq(0)
+      stderr.should contain("undefined method")
+      stderr.should contain("missing_api")
+    end
+
+    it "fails on _literal_js in strict mode" do
+      source = <<-CR
+      require "./src/js"
+
+      class StrictLiteralCode < JS::Code
+        def_to_js strict: true do
+          _literal_js("alert('nope')")
+        end
+      end
+
+      puts StrictLiteralCode.to_js
+      CR
+
+      exit_code, _stdout, stderr = crystal_eval(source)
+      exit_code.should_not eq(0)
+      stderr.should contain("undefined method")
+      stderr.should contain("_literal_js")
+    end
+  end
+end
diff --git a/spec/js/context/console_spec.cr b/spec/js/context/console_spec.cr
new file mode 100644
index 0000000..c9e65bc
--- /dev/null
+++ b/spec/js/context/console_spec.cr
@@ -0,0 +1,34 @@
+require "../../spec_helper"
+
+module JS::Context::APISpec
+  class StrictConsoleCode < JS::Code
+    def_to_js strict: true do
+      console.log("Hello", 7, true, nil)
+      console.info("Info")
+      console.warn("Warn")
+      console.error("Error")
+    end
+  end
+
+  describe "strict browser context console calls" do
+    it "transpiles literal console calls in strict mode" do
+      expected = <<-JS.squish
+      console.log("Hello", 7, true, undefined);
+      console.info("Info");
+      console.warn("Warn");
+      console.error("Error");
+      JS
+
+      StrictConsoleCode.to_js.should eq(expected)
+    end
+  end
+
+  describe "typed console return value" do
+    it "returns an Undefined context wrapper exposing to_js_ref" do
+      result = JS::Context.default.console.log("Hello")
+
+      result.should be_a(JS::Context::Undefined)
+      result.to_js_ref.should eq("console.log(\"Hello\")")
+    end
+  end
+end
diff --git a/spec/js/file/strict_mode_spec.cr b/spec/js/file/strict_mode_spec.cr
new file mode 100644
index 0000000..bc4367f
--- /dev/null
+++ b/spec/js/file/strict_mode_spec.cr
@@ -0,0 +1,21 @@
+require "../../spec_helper"
+
+module JS::File::StrictModeSpec
+  class StrictFile < JS::File
+    js_alias "doc", "document"
+
+    def_to_js strict: true do
+      doc.body.classList.add("active")
+    end
+  end
+
+  describe "StrictFile.to_js" do
+    it "supports strict mode opt-in" do
+      expected = <<-JS.squish
+      document.body.classList.add("active");
+      JS
+
+      StrictFile.to_js.should eq(expected)
+    end
+  end
+end
diff --git a/spec/js/module/strict_mode_spec.cr b/spec/js/module/strict_mode_spec.cr
new file mode 100644
index 0000000..aa9d4b4
--- /dev/null
+++ b/spec/js/module/strict_mode_spec.cr
@@ -0,0 +1,26 @@
+require "../../spec_helper"
+
+module JS::Module::StrictModeSpec
+  class StrictModule < JS::Module
+    js_import Controller, from: "/assets/stimulus.js"
+    js_alias "doc", "document"
+
+    def_to_js strict: true do
+      title = doc.querySelector("title")
+      console.log(title)
+    end
+  end
+
+  describe "StrictModule.to_js" do
+    it "supports strict mode opt-in" do
+      expected = <<-JS.squish
+      import { Controller } from "/assets/stimulus.js";
+      var title;
+      title = document.querySelector("title");
+      console.log(title);
+      JS
+
+      StrictModule.to_js.should eq(expected)
+    end
+  end
+end
diff --git a/spec/spec_helper.cr b/spec/spec_helper.cr
index 1e85a61..4b17f24 100644
--- a/spec/spec_helper.cr
+++ b/spec/spec_helper.cr
@@ -6,3 +6,18 @@ class String
     split(/\n\s*/).join
   end
 end
+
+def crystal_eval(source : String)
+  stdout = IO::Memory.new
+  stderr = IO::Memory.new
+  status = Process.run(
+    "crystal",
+    ["eval", source],
+    chdir: File.expand_path("..", __DIR__),
+    env: {"CRYSTAL_CACHE_DIR" => "/tmp/.crystal-cache-js"},
+    output: stdout,
+    error: stderr
+  )
+
+  {status.exit_code, stdout.to_s, stderr.to_s}
+end
diff --git a/src/ext/bool.cr b/src/ext/bool.cr
index 2fe70bb..c9d1a54 100644
--- a/src/ext/bool.cr
+++ b/src/ext/bool.cr
@@ -2,4 +2,8 @@ struct Bool
   def self.to_js_ref
     "Boolean"
   end
+
+  def to_js_ref
+    self ? "true" : "false"
+  end
 end
diff --git a/src/ext/float.cr b/src/ext/float.cr
new file mode 100644
index 0000000..6d5fbab
--- /dev/null
+++ b/src/ext/float.cr
@@ -0,0 +1,11 @@
+struct Float32
+  def to_js_ref
+    self
+  end
+end
+
+struct Float64
+  def to_js_ref
+    self
+  end
+end
diff --git a/src/ext/nil.cr b/src/ext/nil.cr
new file mode 100644
index 0000000..537cf7e
--- /dev/null
+++ b/src/ext/nil.cr
@@ -0,0 +1,5 @@
+struct Nil
+  def to_js_ref
+    "undefined"
+  end
+end
diff --git a/src/js.cr b/src/js.cr
index 8921990..755a4f7 100644
--- a/src/js.cr
+++ b/src/js.cr
@@ -1,2 +1,3 @@
 require "./js/module"
+require "./js/context/*"
 require "./ext/*"
diff --git a/src/js/code.cr b/src/js/code.cr
index 9f24f15..1334e13 100644
--- a/src/js/code.cr
+++ b/src/js/code.cr
@@ -8,9 +8,13 @@ module JS
       {% JS_ALIASES[name.id.stringify] = aliased_name.id.stringify %}
     end
 
-    macro def_to_js(&blk)
+    macro def_to_js(strict = false, &blk)
       def self.to_js(io : IO)
-        JS::Code._eval_js_block(io, {{@type.resolve}}, {inline: false, nested_scope: true}) {{blk}}
+        JS::Code._eval_js_block(
+          io,
+          {{@type.resolve}},
+          {inline: false, nested_scope: true, strict: {{strict}}}
+        ) {{blk}}
       end
 
       def self.to_js
@@ -32,7 +36,7 @@ module JS
       {% end %}
 
       {% for exp in exps %}
-          {% if exp.is_a?(Call) && exp.name.stringify == "_literal_js" %}
+          {% if exp.is_a?(Call) && exp.name.stringify == "_literal_js" && !opts[:strict] %}
             {{io}} << {{exp.args.first}}
           {% elsif exp.is_a?(Call) && exp.name.stringify == "to_js_call" %}
             {{io}} << {{exp}}
@@ -44,7 +48,7 @@ module JS
           {% elsif exp.is_a?(Call) && !exp.receiver && exp.name.stringify == "await" %}
             {{io}} << "await "
             {% if exp.args.size > 0 %}
-              JS::Code._eval_js_block({{io}}, {{namespace}}, {inline: true, nested_scope: false}) do {{ blk.args.empty? ? "".id : "|#{blk.args.splat}|".id }}
+              JS::Code._eval_js_block({{io}}, {{namespace}}, {inline: true, nested_scope: false, strict: {{opts[:strict]}}}) do {{blk.args.empty? ? "".id : "|#{blk.args.splat}|".id}}
                 {{exp.args.first}}
               end
             {% end %}
@@ -55,19 +59,19 @@ module JS
             {{io}} << "async function("
             {{io}} << {{exp.block.args.splat.stringify}}
             {{io}} << ") {"
-            JS::Code._eval_js_block({{io}}, {{namespace}}, {inline: false, nested_scope: true}) {{exp.block}}
+            JS::Code._eval_js_block({{io}}, {{namespace}}, {inline: false, nested_scope: true, strict: {{opts[:strict]}}}) {{exp.block}}
             {{io}} << "}"
             {% if !opts[:inline] %}
               {{io}} << ";"
             {% end %}
           {% elsif exp.is_a?(Call) && exp.name.stringify == "new" %}
             {{io}} << "new "
-            JS::Code._eval_js_block({{io}}, {{namespace}}, {inline: true, nested_scope: false}) do {{ blk.args.empty? ? "".id : "|#{blk.args.splat}|".id }}
+            JS::Code._eval_js_block({{io}}, {{namespace}}, {inline: true, nested_scope: false, strict: {{opts[:strict]}}}) do {{blk.args.empty? ? "".id : "|#{blk.args.splat}|".id}}
               {{exp.receiver}}
             end
             {{io}} << "("
             {% for arg, index in exp.args %}
-              JS::Code._eval_js_block({{io}}, {{namespace}}, {inline: true, nested_scope: false}) do {{ blk.args.empty? ? "".id : "|#{blk.args.splat}|".id }}
+              JS::Code._eval_js_block({{io}}, {{namespace}}, {inline: true, nested_scope: false, strict: {{opts[:strict]}}}) do {{blk.args.empty? ? "".id : "|#{blk.args.splat}|".id}}
                 {{arg}}
               end
               {% if index < exp.args.size - 1 %}
@@ -78,7 +82,7 @@ module JS
           {% elsif exp.is_a?(Call) && exp.name.stringify == "[]" %}
             {{io}} << {{exp.receiver.stringify}}
             {{io}} << "["
-            JS::Code._eval_js_block({{io}}, {{namespace}}, {inline: true, nested_scope: false}) do {{ blk.args.empty? ? "".id : "|#{blk.args.splat}|".id }}
+            JS::Code._eval_js_block({{io}}, {{namespace}}, {inline: true, nested_scope: false, strict: {{opts[:strict]}}}) do {{blk.args.empty? ? "".id : "|#{blk.args.splat}|".id}}
               {{exp.args.first}}
             end
             {{io}} << "]"
@@ -88,11 +92,11 @@ module JS
           {% elsif exp.is_a?(Call) && exp.name.stringify == "[]=" %}
             {{io}} << {{exp.receiver.stringify}}
             {{io}} << "["
-            JS::Code._eval_js_block({{io}}, {{namespace}}, {inline: true, nested_scope: false}) do {{ blk.args.empty? ? "".id : "|#{blk.args.splat}|".id }}
+            JS::Code._eval_js_block({{io}}, {{namespace}}, {inline: true, nested_scope: false, strict: {{opts[:strict]}}}) do {{blk.args.empty? ? "".id : "|#{blk.args.splat}|".id}}
               {{exp.args.first}}
             end
             {{io}} << "] = "
-            JS::Code._eval_js_block({{io}}, {{namespace}}, {inline: true, nested_scope: false}) do {{ blk.args.empty? ? "".id : "|#{blk.args.splat}|".id }}
+            JS::Code._eval_js_block({{io}}, {{namespace}}, {inline: true, nested_scope: false, strict: {{opts[:strict]}}}) do {{blk.args.empty? ? "".id : "|#{blk.args.splat}|".id}}
               {{exp.args.last}}
             end
             {% if !opts[:inline] %}
@@ -103,7 +107,7 @@ module JS
             {{io}} << "."
             {{io}} << {{exp.name.stringify[0..-2]}}
             {{io}} << " = "
-            JS::Code._eval_js_block({{io}}, {{namespace}}, {inline: true, nested_scope: false}) do {{ blk.args.empty? ? "".id : "|#{blk.args.splat}|".id }}
+            JS::Code._eval_js_block({{io}}, {{namespace}}, {inline: true, nested_scope: false, strict: {{opts[:strict]}}}) do {{blk.args.empty? ? "".id : "|#{blk.args.splat}|".id}}
               {{exp.args.first}}
             end
             {% if !opts[:inline] %}
@@ -111,30 +115,34 @@ module JS
             {% end %}
           {% elsif exp.is_a?(Call) %}
             {% if exp.receiver && exp.args.size == 1 && OPERATOR_CALL_NAMES.includes?(exp.name.stringify) %}
-              JS::Code._eval_js_block({{io}}, {{namespace}}, {inline: true, nested_scope: false}) do {{ blk.args.empty? ? "".id : "|#{blk.args.splat}|".id }}
+              JS::Code._eval_js_block({{io}}, {{namespace}}, {inline: true, nested_scope: false, strict: {{opts[:strict]}}}) do {{blk.args.empty? ? "".id : "|#{blk.args.splat}|".id}}
                 {{exp.receiver}}
               end
               {{io}} << " "
               {{io}} << {{exp.name.stringify}}
               {{io}} << " "
-              JS::Code._eval_js_block({{io}}, {{namespace}}, {inline: true, nested_scope: false}) do {{ blk.args.empty? ? "".id : "|#{blk.args.splat}|".id }}
+              JS::Code._eval_js_block({{io}}, {{namespace}}, {inline: true, nested_scope: false, strict: {{opts[:strict]}}}) do {{blk.args.empty? ? "".id : "|#{blk.args.splat}|".id}}
                 {{exp.args.first}}
               end
             {% else %}
+              {% if opts[:strict] && !exp.receiver && !JS_ALIASES.has_key?(exp.name.stringify) %}
+                JS::Context.default.{{exp.name}}
+              {% end %}
+              {% emitted_from_strict_context = false %}
               {% if exp.receiver %}
                 # TODO: Replace this whole `if` by a recursive call to this macro?
                 {% if exp.receiver.is_a?(Call) %}
-                  JS::Code._eval_js_block({{io}}, {{namespace}}, {inline: true, nested_scope: false}) do {{ blk.args.empty? ? "".id : "|#{blk.args.splat}|".id }}
+                  JS::Code._eval_js_block({{io}}, {{namespace}}, {inline: true, nested_scope: false, strict: {{opts[:strict]}}}) do {{blk.args.empty? ? "".id : "|#{blk.args.splat}|".id}}
                     {{exp.receiver}}
                   end
                 {% elsif exp.receiver.is_a?(Expressions) %}
                   {% for rec_exp in exp.receiver.expressions %}
-                    JS::Code._eval_js_block({{io}}, {{namespace}}, {inline: true, nested_scope: false}) do {{ blk.args.empty? ? "".id : "|#{blk.args.splat}|".id }}
+                    JS::Code._eval_js_block({{io}}, {{namespace}}, {inline: true, nested_scope: false, strict: {{opts[:strict]}}}) do {{blk.args.empty? ? "".id : "|#{blk.args.splat}|".id}}
                       {{rec_exp}}
                     end
                   {% end %}
                 {% elsif (exp.receiver.is_a?(Path) || exp.receiver.is_a?(TypeNode)) && exp.receiver.resolve? %}
-                  {% if exp.receiver.resolve.has_method?(:to_js_ref) %}
+                  {% if exp.receiver.resolve.is_a?(TypeNode) && exp.receiver.resolve.class.has_method?(:to_js_ref) %}
                     {{io}} << {{exp.receiver}}.to_js_ref
                   {% else %}
                     {{io}} << {{exp.receiver.stringify}}
@@ -145,8 +153,11 @@ module JS
                 {% if exp.name.stringify != "_call" %}
                   {{io}} << "."
                 {% end %}
+              {% elsif opts[:strict] && exp.args.empty? && exp.named_args.is_a?(Nop) && !exp.block && !JS_ALIASES.has_key?(exp.name.stringify) %}
+                  {{io}} << JS::Context.default.{{exp.name}}.to_js_ref
+                  {% emitted_from_strict_context = true %}
               {% end %}
-              {% if exp.name.stringify != "_call" %}
+              {% if exp.name.stringify != "_call" && !emitted_from_strict_context %}
                 {{io}} << {{JS_ALIASES[exp.name.stringify] || exp.name.stringify}}
               {% end %}
               {% has_named_args = !exp.named_args.is_a?(Nop) %}
@@ -154,7 +165,7 @@ module JS
                 {{io}} << "("
               {% end %}
               {% for arg, index in exp.args %}
-                JS::Code._eval_js_block({{io}}, {{namespace}}, {inline: true, nested_scope: false}) do {{ blk.args.empty? ? "".id : "|#{blk.args.splat}|".id }}
+                JS::Code._eval_js_block({{io}}, {{namespace}}, {inline: true, nested_scope: false, strict: {{opts[:strict]}}}) do {{blk.args.empty? ? "".id : "|#{blk.args.splat}|".id}}
                   {{arg}}
                 end
                 {% if index < exp.args.size - 1 || exp.block || has_named_args %}
@@ -166,7 +177,7 @@ module JS
                 {% for named_arg, index in exp.named_args %}
                   {{io}} << {{named_arg.name.stringify}}
                   {{io}} << ": "
-                  JS::Code._eval_js_block({{io}}, {{namespace}}, {inline: true, nested_scope: false}) do {{ blk.args.empty? ? "".id : "|#{blk.args.splat}|".id }}
+                  JS::Code._eval_js_block({{io}}, {{namespace}}, {inline: true, nested_scope: false, strict: {{opts[:strict]}}}) do {{blk.args.empty? ? "".id : "|#{blk.args.splat}|".id}}
                     {{named_arg.value}}
                   end
                   {% if index < exp.named_args.size - 1 %}
@@ -182,7 +193,7 @@ module JS
                 {{io}} << "function("
                 {{io}} << {{exp.block.args.splat.stringify}}
                 {{io}} << ") {"
-                JS::Code._eval_js_block({{io}}, {{namespace}}, {inline: false, nested_scope: true}) {{exp.block}}
+                JS::Code._eval_js_block({{io}}, {{namespace}}, {inline: false, nested_scope: true, strict: {{opts[:strict]}}}) {{exp.block}}
                 {{io}} << "}"
               {% end %}
               {% if exp.args.size > 0 || exp.block || exp.name.stringify == "_call" || has_named_args %}
@@ -195,11 +206,11 @@ module JS
           {% elsif exp.is_a?(Path) %}
             {% parent_namespace = namespace.stringify.split("::")[0..-2].join("::").id %}
             {% relative_path = exp.global? ? exp.stringify.gsub(/\A::/, "") : exp %}
-            {% if (type = exp.resolve?) && type.class.has_method?("to_js_ref") %}
+            {% if (type = exp.resolve?) && type.is_a?(TypeNode) && type.class.has_method?("to_js_ref") %}
               {{io}} << {{exp}}.to_js_ref
-            {% elsif (type = parse_type("#{namespace}::#{relative_path.id}").resolve?) && type.class.has_method?("to_js_ref") %}
+            {% elsif (type = parse_type("#{namespace}::#{relative_path.id}").resolve?) && type.is_a?(TypeNode) && type.class.has_method?("to_js_ref") %}
               {{io}} << {{type}}.to_js_ref
-            {% elsif (type = parse_type("#{parent_namespace}::#{relative_path.id}").resolve?) && type.class.has_method?("to_js_ref") %}
+            {% elsif (type = parse_type("#{parent_namespace}::#{relative_path.id}").resolve?) && type.is_a?(TypeNode) && type.class.has_method?("to_js_ref") %}
               {{io}} << {{type}}.to_js_ref
             {% else %}
               {{io}} << {{exp.stringify}}
@@ -207,7 +218,7 @@ module JS
           {% elsif exp.is_a?(ArrayLiteral) %}
             {{io}} << "["
             {% for element, index in exp %}
-              JS::Code._eval_js_block({{io}}, {{namespace}}, {inline: true, nested_scope: false}) do {{ blk.args.empty? ? "".id : "|#{blk.args.splat}|".id }}
+              JS::Code._eval_js_block({{io}}, {{namespace}}, {inline: true, nested_scope: false, strict: {{opts[:strict]}}}) do {{blk.args.empty? ? "".id : "|#{blk.args.splat}|".id}}
                 {{element}}
               end
               {% if index < exp.size - 1 %}
@@ -223,7 +234,7 @@ module JS
             {% for key, i in exp.keys %}
               {{io}} << {{key.id.stringify}}
               {{io}} << ": "
-              JS::Code._eval_js_block({{io}}, {{namespace}}, {inline: true, nested_scope: false}) do {{ blk.args.empty? ? "".id : "|#{blk.args.splat}|".id }}
+              JS::Code._eval_js_block({{io}}, {{namespace}}, {inline: true, nested_scope: false, strict: {{opts[:strict]}}}) do {{blk.args.empty? ? "".id : "|#{blk.args.splat}|".id}}
                 {{exp[key]}}
               end
               {% if i < exp.size - 1 %}
@@ -236,17 +247,17 @@ module JS
             {% end %}
           {% elsif exp.is_a?(If) %}
             {{io}} << "if ("
-            JS::Code._eval_js_block({{io}}, {{namespace}}, {inline: true, nested_scope: false}) do {{ blk.args.empty? ? "".id : "|#{blk.args.splat}|".id }}
+            JS::Code._eval_js_block({{io}}, {{namespace}}, {inline: true, nested_scope: false, strict: {{opts[:strict]}}}) do {{blk.args.empty? ? "".id : "|#{blk.args.splat}|".id}}
               {{exp.cond}}
             end
             {{io}} << ") {"
-            JS::Code._eval_js_block({{io}}, {{namespace}}, {inline: false, nested_scope: false}) do {{ blk.args.empty? ? "".id : "|#{blk.args.splat}|".id }}
+            JS::Code._eval_js_block({{io}}, {{namespace}}, {inline: false, nested_scope: false, strict: {{opts[:strict]}}}) do {{blk.args.empty? ? "".id : "|#{blk.args.splat}|".id}}
               {{exp.then}}
             end
             {{io}} << "}"
             {% if !exp.else.is_a?(Nop) %}
               {{io}} << " else {"
-              JS::Code._eval_js_block({{io}}, {{namespace}}, {inline: false, nested_scope: false}) do {{ blk.args.empty? ? "".id : "|#{blk.args.splat}|".id }}
+              JS::Code._eval_js_block({{io}}, {{namespace}}, {inline: false, nested_scope: false, strict: {{opts[:strict]}}}) do {{blk.args.empty? ? "".id : "|#{blk.args.splat}|".id}}
                 {{exp.else}}
               end
               {{io}} << "}"
@@ -255,7 +266,7 @@ module JS
             {{exp.target}} = nil
             {{io}} << {{exp.target.stringify}}
             {{io}} << " = "
-            JS::Code._eval_js_block({{io}}, {{namespace}}, {inline: true, nested_scope: false}) do {{ blk.args.empty? ? "".id : "|#{blk.args.splat}|".id }}
+            JS::Code._eval_js_block({{io}}, {{namespace}}, {inline: true, nested_scope: false, strict: {{opts[:strict]}}}) do {{blk.args.empty? ? "".id : "|#{blk.args.splat}|".id}}
               {{exp.value}}
             end
             {% if !opts[:inline] %}
@@ -263,7 +274,7 @@ module JS
             {% end %}
           {% elsif exp.is_a?(Return) %}
             {{io}} << "return "
-            JS::Code._eval_js_block({{io}}, {{namespace}}, {inline: true, nested_scope: false}) do {{ blk.args.empty? ? "".id : "|#{blk.args.splat}|".id }}
+            JS::Code._eval_js_block({{io}}, {{namespace}}, {inline: true, nested_scope: false, strict: {{opts[:strict]}}}) do {{blk.args.empty? ? "".id : "|#{blk.args.splat}|".id}}
               {{exp.exp}}
             end
             {% if !opts[:inline] %}
@@ -271,23 +282,23 @@ module JS
             {% end %}
           {% elsif exp.is_a?(ProcLiteral) %}
             {{io}} << "({{exp.args.map(&.name).splat}}) => {"
-            JS::Code._eval_js_block({{io}}, {{namespace}}, {inline: false, nested_scope: false}) do {{blk.args.empty? ? "".id : "|#{blk.args.splat}|".id}}
+            JS::Code._eval_js_block({{io}}, {{namespace}}, {inline: false, nested_scope: false, strict: {{opts[:strict]}}}) do {{blk.args.empty? ? "".id : "|#{blk.args.splat}|".id}}
               {{exp.body}}
             end
             {{io}} << "}"
           {% elsif exp.is_a?(MacroIf) %}
             \{% if {{exp.cond}} %}
-              JS::Code._eval_js_block({{io}}, {{namespace}}, {inline: false, nested_scope: false}) do
+              JS::Code._eval_js_block({{io}}, {{namespace}}, {inline: false, nested_scope: false, strict: {{opts[:strict]}}}) do
                 {{exp.then}}
               end
             \{% else %}
-              JS::Code._eval_js_block({{io}}, {{namespace}}, {inline: false, nested_scope: false}) do
+              JS::Code._eval_js_block({{io}}, {{namespace}}, {inline: false, nested_scope: false, strict: {{opts[:strict]}}}) do
                 {{exp.else}}
               end
             \{% end %}
           {% elsif exp.is_a?(MacroFor) %}
             \{% for {{exp.vars.splat}} in {{exp.exp}} %}
-              JS::Code._eval_js_block({{io}}, {{namespace}}, {inline: false, nested_scope: false}) do
+              JS::Code._eval_js_block({{io}}, {{namespace}}, {inline: false, nested_scope: false, strict: {{opts[:strict]}}}) do
                 {{exp.body}}
               end
             \{% end %}
diff --git a/src/js/context/browser.cr b/src/js/context/browser.cr
new file mode 100644
index 0000000..0be8bdb
--- /dev/null
+++ b/src/js/context/browser.cr
@@ -0,0 +1,15 @@
+require "./console"
+
+module JS
+  module Context
+    class Browser
+      def console : JS::Context::Console
+        JS::Context::Console.new
+      end
+    end
+
+    def self.default : JS::Context::Browser
+      JS::Context::Browser.new
+    end
+  end
+end
diff --git a/src/js/context/console.cr b/src/js/context/console.cr
new file mode 100644
index 0000000..fc27b7b
--- /dev/null
+++ b/src/js/context/console.cr
@@ -0,0 +1,32 @@
+require "./context_object"
+require "./undefined"
+
+module JS
+  module Context
+    class Console < JS::Context::ContextObject
+      def initialize
+        super("console")
+      end
+
+      def log(*args : JS::Context::CallArgument) : JS::Context::Undefined
+        build_call("log", *args)
+      end
+
+      def info(*args : JS::Context::CallArgument) : JS::Context::Undefined
+        build_call("info", *args)
+      end
+
+      def warn(*args : JS::Context::CallArgument) : JS::Context::Undefined
+        build_call("warn", *args)
+      end
+
+      def error(*args : JS::Context::CallArgument) : JS::Context::Undefined
+        build_call("error", *args)
+      end
+
+      private def build_call(name : String, *args : JS::Context::CallArgument) : JS::Context::Undefined
+        JS::Context::Undefined.new(to_js_ref, name, *args)
+      end
+    end
+  end
+end
diff --git a/src/js/context/context_object.cr b/src/js/context/context_object.cr
new file mode 100644
index 0000000..1e1898a
--- /dev/null
+++ b/src/js/context/context_object.cr
@@ -0,0 +1,39 @@
+module JS
+  module Context
+    alias CallArgument = Nil | Bool | Int::Primitive | Float32 | Float64 | String | JS::Context::ContextObject
+
+    abstract class ContextObject
+      getter to_js_ref : String
+
+      protected def initialize(@to_js_ref : String)
+      end
+
+      def initialize(preceding_call_chain : String, method_name : String, *args : JS::Context::CallArgument)
+        @to_js_ref = JS::Context.build_call_chain(preceding_call_chain, method_name, *args)
+      end
+    end
+
+    # Keep chain generation centralized so all browser context wrappers emit identical JS call syntax.
+    def self.build_call_chain(preceding_call_chain : String, method_name : String, *args : JS::Context::CallArgument) : String
+      String.build do |io|
+        unless preceding_call_chain.empty?
+          io << preceding_call_chain
+          io << "."
+        end
+        io << method_name
+        if !preceding_call_chain.empty? || !args.empty?
+          io << "("
+          serialize_args(io, *args)
+          io << ")"
+        end
+      end
+    end
+
+    def self.serialize_args(io : IO, *args : JS::Context::CallArgument) : Nil
+      args.each_with_index do |arg, index|
+        io << ", " unless index.zero?
+        io << arg.to_js_ref
+      end
+    end
+  end
+end
diff --git a/src/js/context/undefined.cr b/src/js/context/undefined.cr
new file mode 100644
index 0000000..2b2c61a
--- /dev/null
+++ b/src/js/context/undefined.cr
@@ -0,0 +1,8 @@
+require "./context_object"
+
+module JS
+  module Context
+    class Undefined < JS::Context::ContextObject
+    end
+  end
+end
diff --git a/src/js/file.cr b/src/js/file.cr
index 6fc9920..ac0fdd5 100644
--- a/src/js/file.cr
+++ b/src/js/file.cr
@@ -45,11 +45,11 @@ module JS
       end
     end
 
-    macro def_to_js(&blk)
-      def_to_js({{@type}}) {{blk}}
+    macro def_to_js(strict = false, &blk)
+      def_to_js({{@type}}, strict: {{strict}}) {{blk}}
     end
 
-    macro def_to_js(namespace, &blk)
+    macro def_to_js(namespace, strict = false, &blk)
       def self.to_js(io : IO)
         @@js_classes.each do |js_class|
           js_class.to_js(io)
@@ -57,7 +57,11 @@ module JS
         @@js_functions.each do |func|
           func.to_js(io)
         end
-        JS::Code._eval_js_block(io, {{namespace}}, {inline: false, nested_scope: true}) {{blk}}
+        JS::Code._eval_js_block(
+          io,
+          {{namespace}},
+          {inline: false, nested_scope: true, strict: {{strict}}}
+        ) {{blk}}
       end
 
       def self.to_js
diff --git a/src/js/function.cr b/src/js/function.cr
index 199785d..35a6811 100644
--- a/src/js/function.cr
+++ b/src/js/function.cr
@@ -37,7 +37,11 @@ module JS
         {% else %}
           io << "function #{function_name}({{blk.args.splat}}) {"
         {% end %}
-        JS::Code._eval_js_block(io, {{@type.resolve}}, {inline: false, nested_scope: true}) {{blk}}
+        JS::Code._eval_js_block(
+          io,
+          {{@type.resolve}},
+          {inline: false, nested_scope: true, strict: false}
+        ) {{blk}}
         io << "}"
       end
 
diff --git a/src/js/method.cr b/src/js/method.cr
index 58e8e55..acf5440 100644
--- a/src/js/method.cr
+++ b/src/js/method.cr
@@ -14,7 +14,11 @@ module JS
 
       def self.to_js(io : IO)
         io << "#{function_name}({{blk.args.splat}}) {"
-        JS::Code._eval_js_block(io, {{@type.resolve}}, {inline: false, nested_scope: true}) {{blk}}
+        JS::Code._eval_js_block(
+          io,
+          {{@type.resolve}},
+          {inline: false, nested_scope: true, strict: false}
+        ) {{blk}}
         io << "}"
       end
 
diff --git a/src/js/module.cr b/src/js/module.cr
index 5687aa7..0f32aa4 100644
--- a/src/js/module.cr
+++ b/src/js/module.cr
@@ -8,8 +8,8 @@ module JS
       @@js_imports << ("import { {{names.map(&.id).splat}} } from \"" + {{from}} + "\";")
     end
 
-    macro def_to_js(&blk)
-      JS::File.def_to_js({{@type}}) {{blk}}
+    macro def_to_js(strict = false, &blk)
+      JS::File.def_to_js({{@type}}, strict: {{strict}}) {{blk}}
 
       def self.to_js(io : IO)
         @@js_imports.join(io, "\n")