Use loose equality (`== null`) instead of strict equality (`=== null` or `=== undefined`) when checking for both null and undefined values. In most JavaScript contexts, null and undefined should be treated equivalently, and loose equality provides a more concise and readable way to handle both cases. This pattern is particularly useful for: - Environment variable checks - Optional configuration properties - Function parameters with default values - Property existence validation Example: ```javascript // Instead of this: if (typeof process.env[address] === 'undefined') missingEnvVariables.add(address); if (startingPosition === 'AT_TIMESTAMP' && !(startingPositionTimestamp !== undefined && startingPositionTimestamp !== null)) { // Use this: if (process.env[address] == null) missingEnvVariables.add(address); if (startingPosition === 'AT_TIMESTAMP' && startingPositionTimestamp == null) { ``` The loose equality check (`== null`) catches both `null` and `undefined` values in a single, readable condition, making code more maintainable and following JavaScript's conventional approach to null safety.