[Using the PPP metric, China is the world’s largest economy. A failing Chinese economy will have global repercussions, including on the U.S. China has replaced the U.S. as the engine of the global economy.]
https://www.cia.gov/the-world-factbook/field/real-gdp-purchasing-power-parity/country-comparison
The CIA Factbook uses PPP.
Real GDP (purchasing power parity)
GDP (purchasing power parity) compares the gross domestic product (GDP) or value of all final goods and services produced within a nation in a given year. A nation’s GDP at purchasing power parity (PPP) exchange rates is the sum value of all goods and services produced in the country valued at prices prevailing in the United States.