Sometimes the NPM package registry is a bit loaded and individual GET HTTP requests emitted by NPM would be responded to with 429 (Too Many Requests) HTTP responses.

It seems that by default NPM might actually try once or twice, but after all it errors out quickly with an error message like this:

npm ERR! 429 Too Many Requests - GET https://registry.npmjs.org/argparse/-/argparse-1.0.10.tgz

Especially in CI systems you want NPM to retry more often with an appropriate back-off, to increase the chance for successfully self-healing transient struggles.

To achieve that you can tune four retry-related configuration parameters documented here. For starters, I now simply set fetch-retries upon installing dependencies:

npm install . --fetch-retries 10