I never came across any piece of news or article stating so until I read this one.  Most news and media usually refer to Taiwan Relations Act from which the United States is obligated to defend or provide arms to Taiwan so Taiwan can be a free democratic state.  It sounds great and too good to be true that US cares so much about Taiwan's democratic values but in reality US also cares about its position as a great power in the West Pacific.

http://thehill.com/opinion/national-security/402286-Taiwan-is-key-to-US-power-in-Pacific

Another action to underline American support for Taiwan is noted in the 2018 National Defense Authorization Act (NDAA); it specifically expresses Congress’s sense that the administration should order Navy ships to call in Taiwanese ports. Congress understands the geographic centrality of Taiwan in the First Island Chain, along with the large strategic value of a free Taiwan in preserving America’s position as a great power in the West Pacific.