prefer-get-or-insert-computed.md

prefer-get-or-insert-computed

📝 Prefer .getOrInsertComputed() when the default value has side effects.

💼🚫 This rule is enabled in the ✅ recommended config. This rule is disabled in the ☑️ unopinionated config.

🔧 This rule is automatically fixable by the --fix CLI option.

Map#getOrInsert() and WeakMap#getOrInsert() always evaluate the default value, even when the key already exists. Use Map#getOrInsertComputed() or WeakMap#getOrInsertComputed() when creating the default value has side effects.

Examples

// ❌
map.getOrInsert(key, call());

// ✅
map.getOrInsertComputed(key, () => call());

// ❌
map.getOrInsert(key, call(key));

// ✅
map.getOrInsertComputed(key, call);