Answers for "spread operator merge two styles"

merge properties of object typescript

const target = { a: 1, b: 2 };
const source = { b: 4, c: 5 };
// Copies source to target object without changing
// target object instance
const returnedTarget = Object.assign(target, source);

multiple styling react native

style={[
			styles.button,
			{ backgroundColor: 'green' }
		  ]}