toMerged

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

This function performs a deep merge, meaning nested objects and arrays are merged recursively.

• 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.

Unlike merge, this function does not mutate the target object.

Signature

function toMerged<T extends Record<PropertyKey, any>, S extends Record<PropertyKey, any>>(target: T, source: S): T & S;

Parameters

• target (T): The target object into which the source object properties will be merged.
• source (S): The source object whose properties will be merged into the target object.

Returns

(T & S): The updated target object with properties from the source object merged in.

Examples

const target = { a: 1, b: { x: 1, y: 2 } };
const source = { b: { y: 3, z: 4 }, c: 5 };
const result = toMerged(target, source);
console.log(result);
// Output: { a: 1, b: { x: 1, y: 3, z: 4 }, c: 5 }

const target = { a: [1, 2], b: { x: 1 } };
const source = { a: [3], b: { y: 2 } };
const result = toMerged(target, source);
console.log(result);
// Output: { a: [3, 2], b: { x: 1, y: 2 } }

const target = { a: null };
const source = { a: [1, 2, 3] };
const result = toMerged(target, source);
console.log(result);
// Output: { a: [1, 2, 3] }

Demo

import "./styles.css";

document.getElementById("app").innerHTML = `
<h1>Hello world</h1>
`;

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