/** * Returns a boolean indicating whether the given global property * is defined and is configurable. */ export function hasConfigurableGlobal(propertyName: string): boolean { const descriptor = Object.getOwnPropertyDescriptor(globalThis, propertyName) // The property is not set at all. if (typeof descriptor === 'undefined') { return false } // The property is set to a getter that returns undefined. if ( typeof descriptor.get === 'function' && typeof descriptor.get() === 'undefined' ) { return false } // The property is set to a value equal to undefined. if (typeof descriptor.get === 'undefined' && descriptor.value == null) { return false } if (typeof descriptor.set === 'undefined' && !descriptor.configurable) { console.error( `[MSW] Failed to apply interceptor: the global \`${propertyName}\` property is non-configurable. This is likely an issue with your environment. If you are using a framework, please open an issue about this in their repository.` ) return false } return true }