Converting blocks to text

Already have a project made with blocks? TextToScratch can turn it into TypeScript so you can keep going in text.

How to use it

• Open the editor on a project that has no TextToScratch code yet (the Text Code button in Scratch, or Open .sb3 in the web editor): its blocks are converted automatically and open as one tab per sprite, plus Stage.ts.
• Or press Convert blocks to text in the editor's toolbar at any time. It asks before replacing code you already have.
• Anything that couldn't be converted exactly is listed in the problems area (in orange) and marked in the code with an // unsupported: ... comment.
• Press Build & Run to replace the blocks with the compiled code.

What converts

Blocks	Code
Hat blocks	whenFlag(() => { }), whenKey, whenClicked, whenBackdrop, whenGreater, onMessage, onClone
if / else, repeat, forever	if (...) { } else if ..., repeat(n, () => { }), forever(() => { })
repeat until, wait until, stop	while (!cond) { }, waitUntil(() => cond), stopAll() / stopThis() / stopOthers()
Operators	+ - * / %, < > === <= >= !==, && || ! with the right brackets; join becomes a template string
Motion / looks / sound / pen / sensing	the API functions and me.x, me.size, me.visible = false, ...
"For this sprite only" variables and lists	let score = 0; / let items: string[] = []; at the top of the sprite file
"For all sprites" variables and lists	properties of export const game = { ... } in Stage.ts, used as game.score (cloud variables go in /** @cloud */ export const cloud)
List blocks	push, insert, remove, pop, list[i], length, indexOf, includes — Scratch's 1-based positions become 0-based indexes
Custom blocks	functions with typed parameters (number, string, boolean); "run without screen refresh" becomes /** @warp */
Comments attached to blocks	// comments

Scratch names that aren't valid identifiers are renamed (my score becomes myScore) and the original name is kept in a comment. Variable types are inferred from how each variable is used; one that holds both numbers and text is declared any.

What doesn't (or changes)

• Extension blocks other than pen (music, video, text to speech, ...) and a few rarely used blocks become // unsupported: <opcode> comments.
• Unknown hat blocks (like when touching) keep their script as a function that nothing calls.
• Loose blocks that aren't under a hat are dropped (they never run).
• Clean-up: block positions, variable monitors on the stage, and the exact shape of some blocks (e.g. Math.round of a mod) are rebuilt by the compiler, so the blocks you get back look a little different but behave the same.
• Projects made with TextToScratch convert too, but constants are inlined, cond ? a : b shows up as an if into a temporary variable, and function return values show up as the hidden __ret variable.