Shameless plug: I wrote my own React introduction—geared more for people that know some JS and HTML, but not necessarily any other JS libraries. More specifically, it very gradually builds up from rendering a single JSX tag to enough components, state, and props to build React's to-do example. I found React has an unusually gradual learning curve—you can really build up concepts bit-by-bit.

EDIT: As per usual, I forgot the link: https://github.com/dahjelle/Programming-Worksheets/blob/mast...