Most popular apps are available as Helm charts. It was not easy to use them in Kosko directly. The all new @kosko/helm package can help you load Helm charts, and of course, it also supports Kubernetes OpenAPI schema validation.
@kosko/helm uses the helm template command to render chart templates and the @kosko/yaml package to load Kubernetes YAML.
First, you have to install the Helm CLI, then install the @kosko/helm package.
npm install @kosko/helm
Next, use the loadChart function to load Helm charts.
const { loadChart } = require("@kosko/helm");
loadChart({
  name: "prom",
  chart: "prometheus",
  repo: "https://prometheus-community.github.io/helm-charts",
  version: "13.6.0",
  values: {
    server: {
      persistentVolume: {
        enabled: true
      }
    }
  }
});
See loading Helm chart for more details.