defaults

INFO

This function is only available in es-toolkit/compat for compatibility reasons. It either has alternative native JavaScript APIs or isn’t fully optimized yet.

When imported from es-toolkit/compat, it behaves exactly like lodash and provides the same functionalities, as detailed here.

Assigns default values to an object, ensuring that certain properties do not remain undefined. It sets default values for properties that are either undefined or inherited from Object.prototype.

You can pass in multiple objects to define these default values, and they will be applied in order from left to right. Once a property has been assigned a value, any subsequent values for that property will be ignored.

Note: This function modifies the first argument, object. If you want to keep object unchanged, consider using toDefaulted instead.

Signature

function defaults<T extends object>(object: T): NonNullable<T>;
function defaults<T extends object, S extends object>(object: T, source: S): NonNullable<T & S>;
function defaults<T extends object, S1 extends object, S2 extends object>(
  object: T,
  source1: S1,
  source2: S2
): NonNullable<T & S1 & S2>;
function defaults<T extends object, S1 extends object, S2 extends object, S3 extends object>(
  object: T,
  source1: S1,
  source2: S2,
  source3: S3
): NonNullable<T & S1 & S2 & S3>;
function defaults<T extends object, S1 extends object, S2 extends object, S3 extends object, S4 extends object>(
  object: T,
  source1: S1,
  source2: S2,
  source3: S3,
  source4: S4
): NonNullable<T & S1 & S2 & S3 & S4>;
function defaults<T extends object, S extends object>(object: T, ...sources: S[]): object;

Parameters

• object (T): The target object that will receive default values.
• sources (S[]): The objects that specifies the default values to apply.

Returns

(object): The object that has been updated with default values from sources, ensuring that all properties are defined and none are left as undefined.

Examples

defaults({ a: 1 }, { a: 2, b: 2 }, { c: 3 }); // { a: 1, b: 2, c: 3 }
defaults({ a: 1, b: 2 }, { b: 3 }, { c: 3 }); // { a: 1, b: 2, c: 3 }
defaults({ a: null }, { a: 1 }); // { a: null }
defaults({ a: undefined }, { a: 1 }); // { a: 1 }