diff --git a/test/infra/Dockerfile.emba b/test/infra/Dockerfile.emba
index 3944f7cca7e..6be67a95e75 100644
--- a/test/infra/Dockerfile.emba
+++ b/test/infra/Dockerfile.emba
@@ -71,9 +71,12 @@ RUN apt-get update && \
 # Install clangd, tsserver, rust-analyzer.
 RUN apt-get update && \
     apt-get install -y --no-install-recommends -o=Dpkg::Use-Pty=0 \
-      clangd node-typescript rust-analyzer cargo \
+      clangd npm node-typescript rust-analyzer cargo \
     && rm -rf /var/lib/apt/lists/*
 
+RUN npm install -g typescript-language-server typescript
+RUN npm install -g vscode-json-languageserver
+
 # eclipse-jdt-ls is planned as Java language server.
 # See <https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=1024246>.