Where to start writing a Tetris game? What is the most important behavior, which is not yet implemented?
You can't have a Tetris without falling tetrominoes, so that would be one place to start. But already that is quite a complex feature.
With TDD we prefer to start small. So let's start by implementing falling 1×1 blocks.
Open the test/FallingBlocks.test.mjs file.
Run this project's tests in a terminal with the npm run autotest command. It'll run the tests automatically whenever a
file is saved, until you stop it with Ctrl+C. At first there should be one failing test, "The board starts empty".
Implement enough of src/Board.mjs to make the one failing test pass.
Then uncomment the next test: remove the /* */ comment marks, or enable a disabled tests by changing xit to it.
Uncomment and make the tests pass, one test at a time, until all the tests as passing.
P.S. The equalShape assertion is a custom assertion to improve the readability of this project's tests. It has been
implemented in test/testing.mjs.