diff --git a/pkgs/development/compilers/ghcjs-ng/8.4/dep-overrides.nix b/pkgs/development/compilers/ghcjs-ng/8.4/dep-overrides.nix
new file mode 100644
index 000000000000..2d0ed55c6cd1
--- /dev/null
+++ b/pkgs/development/compilers/ghcjs-ng/8.4/dep-overrides.nix
@@ -0,0 +1,7 @@
+{ haskellLib }:
+
+let inherit (haskellLib) dontCheck doJailbreak;
+in self: super: {
+  haddock-library-ghcjs = dontCheck super.haddock-library-ghcjs;
+  haddock-api-ghcjs = doJailbreak super.haddock-api-ghcjs;
+}
diff --git a/pkgs/development/compilers/ghcjs-ng/8.4/git.json b/pkgs/development/compilers/ghcjs-ng/8.4/git.json
new file mode 100644
index 000000000000..2d4a7a42667b
--- /dev/null
+++ b/pkgs/development/compilers/ghcjs-ng/8.4/git.json
@@ -0,0 +1,6 @@
+{
+  "url": "https://github.com/ghcjs/ghcjs",
+  "rev": "c494a598d1e5b6d70ddcb97177dc4b6cc71f5bd0",
+  "sha256": "1gpn1y3m2gk2x4anfh11p4cp49blabj761wicawvkw0w9bfhcfhn",
+  "fetchSubmodules": true
+}
diff --git a/pkgs/development/compilers/ghcjs-ng/8.4/stage0.nix b/pkgs/development/compilers/ghcjs-ng/8.4/stage0.nix
new file mode 100644
index 000000000000..051b0a19b5b5
--- /dev/null
+++ b/pkgs/development/compilers/ghcjs-ng/8.4/stage0.nix
@@ -0,0 +1,175 @@
+{ callPackage, configuredSrc }:
+
+{
+
+  ghcjs = callPackage
+    ({ mkDerivation, aeson, array, attoparsec, base, base16-bytestring
+    , base64-bytestring, binary, bytestring, Cabal, containers
+    , cryptohash, data-default, deepseq, directory, executable-path
+    , filepath, ghc-api-ghcjs, ghc-boot, ghc-paths, ghci-ghcjs
+    , ghcjs-th, haddock-api-ghcjs, hashable, haskell-src-exts
+    , haskell-src-meta, http-types, HUnit, lens, lifted-base, mtl
+    , network, optparse-applicative, parallel, parsec, process, random
+    , regex-posix, safe, shelly, split, stdenv, stringsearch, syb
+    , system-fileio, system-filepath, tar, template-haskell
+    , template-haskell-ghcjs, terminfo, test-framework
+    , test-framework-hunit, text, time, transformers
+    , transformers-compat, unix, unix-compat, unordered-containers
+    , vector, wai, wai-app-static, wai-extra, wai-websockets, warp
+    , webdriver, websockets, wl-pprint-text, yaml
+    }:
+    mkDerivation {
+      pname = "ghcjs";
+      version = "8.4.0.1";
+      src = configuredSrc + /.;
+      isLibrary = true;
+      isExecutable = true;
+      enableSeparateDataOutput = true;
+      setupHaskellDepends = [
+        base Cabal containers directory filepath process template-haskell
+        transformers
+      ];
+      libraryHaskellDepends = [
+        aeson array attoparsec base base16-bytestring base64-bytestring
+        binary bytestring Cabal containers cryptohash data-default deepseq
+        directory filepath ghc-api-ghcjs ghc-boot ghc-paths ghci-ghcjs
+        ghcjs-th hashable haskell-src-exts haskell-src-meta lens mtl
+        optparse-applicative parallel parsec process regex-posix safe split
+        stringsearch syb template-haskell template-haskell-ghcjs text time
+        transformers unordered-containers vector wl-pprint-text yaml
+      ];
+      executableHaskellDepends = [
+        aeson base binary bytestring Cabal containers directory
+        executable-path filepath ghc-api-ghcjs ghc-boot haddock-api-ghcjs
+        lens mtl optparse-applicative process shelly system-fileio
+        system-filepath tar terminfo text time transformers
+        transformers-compat unix unix-compat unordered-containers vector
+        yaml
+      ];
+      testHaskellDepends = [
+        aeson base bytestring data-default deepseq directory http-types
+        HUnit lens lifted-base network optparse-applicative process random
+        shelly system-fileio system-filepath test-framework
+        test-framework-hunit text time transformers unordered-containers
+        wai wai-app-static wai-extra wai-websockets warp webdriver
+        websockets yaml
+      ];
+      description = "Haskell to JavaScript compiler";
+      license = stdenv.lib.licenses.mit;
+    }) {};
+
+  ghc-api-ghcjs = callPackage
+    ({ mkDerivation, array, base, binary, bytestring, containers
+    , deepseq, directory, filepath, ghc-boot, ghc-boot-th, ghci-ghcjs
+    , hpc, process, stdenv, template-haskell-ghcjs, terminfo, time
+    , transformers, unix
+    }:
+    mkDerivation {
+      pname = "ghc-api-ghcjs";
+      version = "8.4.0";
+      src = configuredSrc + /lib/ghc-api-ghcjs;
+      libraryHaskellDepends = [
+        array base binary bytestring containers deepseq directory filepath
+        ghc-boot ghc-boot-th ghci-ghcjs hpc process template-haskell-ghcjs
+        terminfo time transformers unix
+      ];
+      homepage = "http://www.haskell.org/ghc/";
+      description = "The GHC API (customized for GHCJS)";
+      license = stdenv.lib.licenses.bsd3;
+    }) {};
+
+  ghci-ghcjs = callPackage
+    ({ mkDerivation, array, base, binary, bytestring, containers
+    , deepseq, filepath, ghc-boot, ghc-boot-th, stdenv
+    , template-haskell-ghcjs, transformers, unix
+    }:
+    mkDerivation {
+      pname = "ghci-ghcjs";
+      version = "8.4.0";
+      src = configuredSrc + /lib/ghci-ghcjs;
+      libraryHaskellDepends = [
+        array base binary bytestring containers deepseq filepath ghc-boot
+        ghc-boot-th template-haskell-ghcjs transformers unix
+      ];
+      description = "The library supporting GHC's interactive interpreter (customized for GHCJS)";
+      license = stdenv.lib.licenses.bsd3;
+    }) {};
+
+  ghcjs-th = callPackage
+    ({ mkDerivation, base, binary, bytestring, containers, ghc-prim
+    , ghci-ghcjs, stdenv, template-haskell-ghcjs
+    }:
+    mkDerivation {
+      pname = "ghcjs-th";
+      version = "0.1.0.0";
+      src = configuredSrc + /lib/ghcjs-th;
+      libraryHaskellDepends = [
+        base binary bytestring containers ghc-prim ghci-ghcjs
+        template-haskell-ghcjs
+      ];
+      homepage = "http://github.com/ghcjs";
+      license = stdenv.lib.licenses.mit;
+    }) {};
+
+  haddock-api-ghcjs = callPackage
+    ({ mkDerivation, array, base, bytestring, Cabal, containers, deepseq
+    , directory, filepath, ghc-api-ghcjs, ghc-boot, ghc-paths
+    , haddock-library-ghcjs, hspec, hspec-discover, QuickCheck, stdenv
+    , transformers, xhtml
+    }:
+    mkDerivation {
+      pname = "haddock-api-ghcjs";
+      version = "2.20.0";
+      src = configuredSrc + /lib/haddock-api-ghcjs;
+      enableSeparateDataOutput = true;
+      libraryHaskellDepends = [
+        array base bytestring Cabal containers deepseq directory filepath
+        ghc-api-ghcjs ghc-boot ghc-paths haddock-library-ghcjs transformers
+        xhtml
+      ];
+      testHaskellDepends = [
+        array base bytestring Cabal containers deepseq directory filepath
+        ghc-api-ghcjs ghc-boot ghc-paths haddock-library-ghcjs hspec
+        QuickCheck transformers xhtml
+      ];
+      testToolDepends = [ hspec-discover ];
+      homepage = "http://www.haskell.org/haddock/";
+      description = "A documentation-generation tool for Haskell libraries";
+      license = stdenv.lib.licenses.bsd3;
+    }) {};
+
+  haddock-library-ghcjs = callPackage
+    ({ mkDerivation, base, base-compat, bytestring, containers, deepseq
+    , directory, filepath, haddock-library, hspec, hspec-discover
+    , optparse-applicative, QuickCheck, stdenv, transformers, tree-diff
+    }:
+    mkDerivation {
+      pname = "haddock-library-ghcjs";
+      version = "1.6.0";
+      src = configuredSrc + /lib/haddock-library-ghcjs;
+      libraryHaskellDepends = [
+        base bytestring containers deepseq transformers
+      ];
+      testHaskellDepends = [
+        base base-compat bytestring containers deepseq directory filepath
+        haddock-library hspec optparse-applicative QuickCheck transformers
+        tree-diff
+      ];
+      testToolDepends = [ hspec-discover ];
+      homepage = "http://www.haskell.org/haddock/";
+      description = "Library exposing some functionality of Haddock";
+      license = stdenv.lib.licenses.bsd3;
+    }) {};
+
+  template-haskell-ghcjs = callPackage
+    ({ mkDerivation, base, ghc-boot-th, pretty, stdenv }:
+    mkDerivation {
+      pname = "template-haskell-ghcjs";
+      version = "2.13.0.0";
+      src = configuredSrc + /lib/template-haskell-ghcjs;
+      libraryHaskellDepends = [ base ghc-boot-th pretty ];
+      description = "Support library for Template Haskell (customized for GHCJS)";
+      license = stdenv.lib.licenses.bsd3;
+    }) {};
+
+}
diff --git a/pkgs/development/haskell-modules/configuration-ghc-8.4.x.nix b/pkgs/development/haskell-modules/configuration-ghc-8.4.x.nix
index 70624d1ed6a8..12fd59748307 100644
--- a/pkgs/development/haskell-modules/configuration-ghc-8.4.x.nix
+++ b/pkgs/development/haskell-modules/configuration-ghc-8.4.x.nix
@@ -105,6 +105,9 @@ self: super: {
   ## hspec-discover ==2.4.8
   hspec-discover = super.hspec-discover_2_5_0;
 
+  # https://github.com/jcristovao/enclosed-exceptions/issues/12
+  enclosed-exceptions = dontCheck super.enclosed-exceptions;
+
   ## On Hackage:
 
   ## Upstreamed, awaiting a Hackage release
@@ -450,7 +453,7 @@ self: super: {
   matrix = self.matrix_0_3_6_1;
   pandoc = self.pandoc_2_2;
   pandoc-types = self.pandoc-types_1_17_4_2;
-  wl-pprint-text = self.wl-pprint-text_1_1_1_1;
+  wl-pprint-text = self.wl-pprint-text_1_2_0_0;
   base-compat = self.base-compat_0_10_1;
 
   # https://github.com/xmonad/xmonad/issues/155
diff --git a/pkgs/top-level/haskell-packages.nix b/pkgs/top-level/haskell-packages.nix
index 837f8eb794d0..c00bce430c3c 100644
--- a/pkgs/top-level/haskell-packages.nix
+++ b/pkgs/top-level/haskell-packages.nix
@@ -95,6 +95,13 @@ in rec {
       stage0 = ../development/compilers/ghcjs-ng/8.2/stage0.nix;
       ghcjsDepOverrides = callPackage ../development/compilers/ghcjs-ng/8.2/dep-overrides.nix {};
     };
+    ghcjs84 = callPackage ../development/compilers/ghcjs-ng rec {
+      bootPkgs = packages.ghc842;
+      inherit (bootPkgs) alex happy;
+      ghcjsSrcJson = ../development/compilers/ghcjs-ng/8.4/git.json;
+      stage0 = ../development/compilers/ghcjs-ng/8.4/stage0.nix;
+      ghcjsDepOverrides = callPackage ../development/compilers/ghcjs-ng/8.4/dep-overrides.nix {};
+    };
 
     # The integer-simple attribute set contains all the GHC compilers
     # build with integer-simple instead of integer-gmp.
@@ -169,6 +176,12 @@ in rec {
       compilerConfig = callPackage ../development/haskell-modules/configuration-ghc-8.2.x.nix { };
       packageSetConfig = callPackage ../development/haskell-modules/configuration-ghcjs.nix { };
     };
+    ghcjs84 = callPackage ../development/haskell-modules rec {
+      buildHaskellPackages = ghc.bootPkgs;
+      ghc = bh.compiler.ghcjs84;
+      compilerConfig = callPackage ../development/haskell-modules/configuration-ghc-8.4.x.nix { };
+      packageSetConfig = callPackage ../development/haskell-modules/configuration-ghcjs.nix { };
+    };
 
     # The integer-simple attribute set contains package sets for all the GHC compilers
     # using integer-simple instead of integer-gmp.