build: auto generate snippet install instructions (#447)

* remove unused file

* create-snippet-instrucitons.js

* update gitignore

* nits

Author: jooohhn

.gitignore

@@ -10,6 +10,7 @@ amplitude.js
 amplitude.esm.js
 amplitude.min.js
 amplitude-snippet.min.js
+amplitude-snippet-instructions.js
 amplitude-segment-snippet.min.js
 .watchmanconfig
 package-lock.json

release.config.js

@@ -16,7 +16,7 @@ module.exports = {
     "@semantic-release/npm",
     ["@semantic-release/exec", {
       "prepareCmd": "make release",
-      "publishCmd": "python scripts/deploy_s3.py --version ${nextRelease.version}",
+      "publishCmd": "node scripts/create-snippet-instructions.js && python scripts/deploy_s3.py --version ${nextRelease.version}",
       "failCmd": "npm unpublish amplitude-js@${nextRelease.version}"
     }],
     ["@semantic-release/github", {

scripts/create-snippet-instructions.js

@@ -0,0 +1,17 @@
+const fs = require('fs');
+const path = require('path');
+
+const cwd = process.cwd();
+const instructionsFileName = path.join(cwd, 'amplitude-snippet-instructions.js');
+
+const snippetFilename = path.join(cwd, 'amplitude-snippet.min.js');
+const snippet = fs.readFileSync(snippetFilename, 'utf-8');
+
+const script = `<script type="text/javascript">
+${snippet}
+amplitude.getInstance().init("YOUR_API_KEY_HERE")
+</script>
+`;
+fs.writeFileSync(instructionsFileName, script);
+
+console.log('Created amplitude-snippet-instructions.js');