[ci] Create hermes-engine-darwin npm package

Notably the symbolic links need to be stripped from the framework bundle,
as npm by design does not support symbolic links to exist in packages.
However, seeing as we already package distinct versions of the framework
in distinct npm packages, there isn't any need to support multiple
versions of Hermes in a single framework bundle; so this should be fine.

.circleci/config.yml

@@ -27,6 +27,7 @@ workflows:
             - android
             - linux
             - macos
+            - build-macos-runtime
             - windows
       - test-linux
       - test-macos

npm/.gitignore

@@ -1,6 +1,11 @@
 *.tar.gz
 *.tgz
+*.sha256
 android
 node_modules
 osx-bin
 package-lock.json
+destroot
+LICENSE
+README.md
+hermes.podspec

npm/hermes-engine-darwin/README.md

@@ -0,0 +1,12 @@
+## Hermes
+
+Hermes is a small and lightweight JavaScript VM optimized for running React
+Native apps on macOS.
+
+See [hermesengine.dev](https://hermesengine.dev) for more information.
+
+This package contains a Hermes bytecode compiler for macOS, plus macOS runtime
+framework.
+
+Additional tools are available in
+[hermes-engine-cli](https://www.npmjs.com/package/hermes-engine-cli).

npm/hermes-engine-darwin/package.json

@@ -0,0 +1,23 @@
+{
+  "name": "hermes-engine-darwin",
+  "version": "%VERSION%",
+  "private": false,
+  "description": "A JavaScript engine optimized for running React Native on macOS",
+  "license": "MIT",
+  "repository": {
+    "type": "git",
+    "url": "git@github.com:facebook/hermes.git"
+  },
+  "scripts": {
+    "strip-symlinks-from-framework": "rm -rf destroot/Library/Frameworks/hermes.framework/{Headers,Resources,hermes} && mv destroot/Library/Frameworks/hermes.framework/Versions/0/* destroot/Library/Frameworks/hermes.framework/ && rm -rf destroot/Library/Frameworks/hermes.framework/Versions && install_name_tool -id @rpath/hermes.framework/hermes destroot/Library/Frameworks/hermes.framework/hermes",
+    "prepack": "npm run-script strip-symlinks-from-framework"
+  },
+  "files": [
+    "LICENSE",
+    "README.md",
+    "hermes.podspec",
+    "destroot/bin/hermesc",
+    "destroot/include/**/*",
+    "destroot/Library/**/*"
+  ]
+}

npm/unpack-builds.js

@@ -134,6 +134,10 @@ var inputs = [
   {
     name: "hermes-cli-darwin-v" + releaseVersion + ".tar.gz",
     dest: "osx-bin"
+  },
+  {
+    name: "hermes-runtime-darwin-v" + releaseVersion + ".tar.gz",
+    dest: ".",
   }
 ]