Use defensive programming patterns to prevent null-related issues before they occur. This includes creating safe object copies to prevent mutations, using explicit null/undefined checks, and initializing objects safely. Key practices: - Create defensive copies using spread syntax when you don't want to expose the underlying object: `{ ...originalObject }` instead of direct assignment - Use explicit checks for empty values: `message.length === 0` instead of `message === ""` - Initialize objects with null prototype when appropriate: `{ __proto__: null }` to prevent prototype pollution - Be explicit with nullish coalescing defaults: carefully consider whether `?? true` or `?? false` is the correct default Example: ```javascript // Good - defensive copy prevents mutation ObjectAssign(internals, { core, nodeGlobals: { ...nodeGlobals } }); // Good - explicit length check const formattedMessage = message.length === 0 ? "" : `${message} `; // Good - null prototype prevents pollution attributes = { __proto__: null }; ``` This approach prevents null reference errors, unintended mutations, and makes null handling intentions explicit in the code.