mergeWith

Import from @varavel/vdl-plugin-sdk/utils/objects.

function mergeWith<T, S>(
   target, 
   source, 
   merge): T & S;

Merges the properties of the source object into the target object.

You can provide a custom merge function to control how properties are merged. It should return the value to be set in the target object.

If it returns undefined, a default deep merge will be applied for arrays and objects:

• If a property in the source object is an array or an object and the corresponding property in the target object is also an array or object, they will be merged.
• If a property in the source object is undefined, it will not overwrite a defined property in the target object.

Note that this function mutates the target object.

Type Parameters

Type Parameter	Description
T extends Record\<PropertyKey, any>	Type of the target object.
S extends Record\<PropertyKey, any>	Type of the source object.

Parameters

Parameter	Type	Description
target	T	The target object into which the source object properties will be merged. This object is modified in place.
source	S	The source object whose properties will be merged into the target object.
merge	(targetValue, sourceValue, key, target, source) => any	A custom merge function that defines how properties should be combined. It receives the following arguments: - targetValue: The current value of the property in the target object. - sourceValue: The value of the property in the source object. - key: The key of the property being merged. - target: The target object. - source: The source object.

Returns

T & S

The updated target object with properties from the source object merged in.

Examples

const target = { a: 1, b: 2 };
const source = { b: 3, c: 4 };

mergeWith(target, source, (targetValue, sourceValue) => {
  if (typeof targetValue === 'number' && typeof sourceValue === 'number') {
    return targetValue + sourceValue;
  }
});
// Returns { a: 1, b: 5, c: 4 }

const target = { a: [1], b: [2] };
const source = { a: [3], b: [4] };

const result = mergeWith(target, source, (objValue, srcValue) => {
  if (Array.isArray(objValue)) {
    return objValue.concat(srcValue);
  }
});

expect(result).toEqual({ a: [1, 3], b: [2, 4] });