assignmentOperatorShorthands

Prefer logical assignment operator shorthand expressions.

✅ This rule is included in the ts stylistic and stylisticStrict presets.

ES2021 introduced logical assignment operators (||=, &&=, ??=) that combine logical operations with assignment. These shorthand operators make code more concise and express intent more clearly.

For example, a = a || b can be written as a ||= b. This pattern is common for providing default values or conditionally updating variables.

Examples

❌ Incorrect

let value = 0;
value = value || 1;

let config: Config | undefined;
Error ts(2749)  ― 'Config' refers to a value, but is being used as a type here. Did you mean 'typeof Config'?
config = config ?? getDefaultConfig();

let enabled = false;
enabled = enabled && isFeatureAvailable();

✅ Correct

let value = 0;
value ||= 1;

let config: Config | undefined;
Error ts(2749)  ― 'Config' refers to a value, but is being used as a type here. Did you mean 'typeof Config'?
config ??= getDefaultConfig();

let enabled = false;
enabled &&= isFeatureAvailable();

Options

This rule is not configurable.

When Not To Use It

If you need to support environments that do not have ES2021 support, you may need to avoid using logical assignment operators. You may also prefer the more explicit expanded form if you find it more readable.

Further Reading

• MDN: Logical OR assignment (||=)
• MDN: Logical AND assignment (&&=)
• MDN: Nullish coalescing assignment (??=)

Equivalents in Other Linters

• ESLint: logical-assignment-operators