I see that the majority upvoted to the "ES6" because ES6 is plain javascript that has more features to the typescript, such as classes, arrow functions and so on. I believe that ES6 is better for the API.
How does ES6 javascript have more features than typescript? TypeScript is a superset of Javascript. Also you can do more with Typescript than just ES6. You can set your compiler to output ES6 but you can use ES7 or ES8.