DIOP0101EnvironmentCI gate
Node.js outside the supported range
The Node.js running Diopter is not in the range Angular supports for the installed version.
What it means
Angular's build tools are tested against specific Node.js lines. Outside the range, ng build may refuse to start or fail in ways that look unrelated.
How to fix it
Switch to a supported Node.js with nvm, fnm or volta. Pin it in .nvmrc / engines.node so the team and CI use the same one (see DIOP0104).
What it looks like
As printed by diopter check; the UI and the Markdown report show the same finding with its location.
[DIOP0101] Node.js 18.20.4 is outside the range supported by Angular 21.2.12 (^20.19.0 || ^22.12.0 || ^24.0.0).
fix: Switch Node.js version (e.g. with nvm, fnm or volta).In CI
Fails
diopter check unless --fail-on none.In the UI
The Environment tab, from
diopter next to your dev server, or the static report from diopter build.For agents
MCP tool
get-report (diopter mcp).