Deep clone

deep-clone-1.js

function deepClone( obj ) {
	const clone = { ...obj };

	Object.entries( clone ).forEach( ( [ key, value ] ) => {
		if ( value && typeof value === 'object' ) {
			clone[ key ] = deepClone( value );
		}
	} );

	return clone;
}

deep-clone-2.js

function deepClone( obj ) {
	const transformed = Object.entries( obj ).map( ( [ key, value ] ) => {
		return [ key, value && typeof value === 'object' ? deepClone( value ) : value ];
	} );

	return Object.fromEntries( transformed );
}