diff --git a/packages/aws-cdk/.gitignore b/packages/aws-cdk/.gitignore
index 778ab4bcae6a9..ba79b3b0cb5c5 100644
--- a/packages/aws-cdk/.gitignore
+++ b/packages/aws-cdk/.gitignore
@@ -42,3 +42,4 @@ lib/vendor/noctilucent/*
 .DS_Store
 
 junit.xml
+tmp/
diff --git a/packages/aws-cdk/.npmignore b/packages/aws-cdk/.npmignore
index a5f61214eee06..c59a8edc18921 100644
--- a/packages/aws-cdk/.npmignore
+++ b/packages/aws-cdk/.npmignore
@@ -31,3 +31,4 @@ junit.xml
 
 generate.sh
 lib/vendor/noctilucent/Dockerfile
+tmp/
diff --git a/packages/aws-cdk/generate.sh b/packages/aws-cdk/generate.sh
index 65655572bf459..f27a9e2845c7f 100755
--- a/packages/aws-cdk/generate.sh
+++ b/packages/aws-cdk/generate.sh
@@ -18,10 +18,15 @@ HERE
 # Download noctilucent wasm-pack build
 NOCTILUCENT_VERSION=0.1.2
 PACK_URL=https://github.com/iph/noctilucent/releases/download/v${NOCTILUCENT_VERSION}/wasm-pack.zip
+zipfile=$PWD/tmp/noctilucent-wasm-${NOCTILUCENT_VERSION}.zip
 outdir=lib/vendor/noctilucent
 
-mkdir -p $outdir
-(cd $outdir && curl -sSfLo wasm-pack.zip "$PACK_URL" && unzip -o wasm-pack.zip)
+mkdir -p tmp
+if [[ ! -f "$zipfile" ]]; then
+    curl -sSfLo "$zipfile" "$PACK_URL"
+fi
+
+(cd $outdir && unzip -qo $zipfile)
 
 # Don't need these files
-rm $outdir/{.gitignore,README.md,package.json,wasm-pack.zip}
+rm -f $outdir/{.gitignore,README.md,package.json}