Always validate environment variables with proper type checking, fallback values, and defensive handling to prevent runtime failures and unexpected behavior.
Always validate environment variables with proper type checking, fallback values, and defensive handling to prevent runtime failures and unexpected behavior.
Environment variables can be undefined, have incorrect types, or contain invalid values. Implement defensive validation patterns that ensure your application gracefully handles these scenarios:
// Bad: Direct usage without validation
const timeout = +process.env.CYPRESS_VERIFY_TIMEOUT || 30000
const baseUrl = process.env.CYPRESS_DOWNLOAD_MIRROR
// Good: Defensive validation with proper fallbacks
const getVerifyTimeout = (): number => {
const verifyTimeout = +(process.env.CYPRESS_VERIFY_TIMEOUT || 'NaN')
if (_.isNumber(verifyTimeout) && !_.isNaN(verifyTimeout)) {
return verifyTimeout
}
return 30000
}
const getBaseUrl = (): string => {
const baseUrl = process.env.CYPRESS_DOWNLOAD_MIRROR
if (!baseUrl?.endsWith('/')) {
return baseUrl ? baseUrl + '/' : defaultBaseUrl
}
return baseUrl || defaultBaseUrl
}
// Remember: Environment variables are always strings
const forceColor = process.env.FORCE_COLOR === '0' // not === 0
Key principles:
CYPRESS_CRASH_REPORTSEnter the URL of a public GitHub repository