We are an open community of developers, technical writers, and learners building resources for a better Web, regardless of brand, browser, or platform. Anyone can contribute, and each person who does contribute has an impact on millions of readers. Learn how to contribute and drive innovation on the Open Web.| developer.mozilla.org
The Object.assign() static method copies all enumerable own properties from one or more source objects to a target object. It returns the modified target object.| developer.mozilla.org
The concat() method of Array instances is used to merge two or more arrays. This method does not change the existing arrays, but instead returns a new array.| developer.mozilla.org
The Object type represents one of JavaScript's data types. It is used to store various keyed collections and more complex entities. Objects can be created using the Object() constructor or the object initializer / literal syntax.| MDN Web Docs
A shallow copy of an object is a copy whose properties share the same references (point to the same underlying values) as those of the source object from which the copy was made. As a result, when you change either the source or the copy, you may also cause the other object to change too. That behavior contrasts with the behavior of a deep copy, in which the source and copy are completely independent.| developer.mozilla.org
The structured clone algorithm copies complex JavaScript objects. It is used internally when invoking structuredClone(), to transfer data between Workers via postMessage(), storing objects with IndexedDB, or copying objects for other APIs.| MDN Web Docs
The map() method of Array instances creates a new array populated with the results of calling a provided function on every element in the calling array.| MDN Web Docs
Introduction This Ecma Standard defines the ECMAScript 2025 Language. It is the sixteenth edition of the ECMAScript Language Specification. Since publication of the first edition in 1997, ECMAScript has grown to be one of the world's most widely used general-purpose programming languages. It is| tc39.es
