Saving & Loading

Two calls cover persistence:

const state = engine.serializeWorkspace();   // plain JSON-serializable object
engine.loadWorkspace(state);                 // restore it

The state is Blockly’s standard JSON workspace serialization — store it wherever you like:

// save
localStorage.setItem("program", JSON.stringify(engine.serializeWorkspace()));

// restore
const saved = localStorage.getItem("program");
if (saved) engine.loadWorkspace(JSON.parse(saved));

Restoring re-renders all mounted views (workspace, codespace, preview, code editor) in their current modes — saved state carries the program, not the presentation. A program saved in iconic mode loads fine into a session running python mode.

Namespacing in saved state

Inside the serialized JSON, your blocks appear under their namespaced Blockly type — morphic:text_print, not text_print (see Block identifiers). Practical consequences:

• Don’t post-process saved state with clean identifiers in mind; the morphic: prefix is expected and required for loading.
• Saved state is coupled to your definitions: loading state that references a block you’ve since removed or renamed fails the same way it would in plain Blockly. Treat definition identifiers as a stable, versioned contract once users have saved programs.
• Blockly stock blocks used as shadows/placeholders (math_number, text) appear under their unprefixed names — that’s correct too.