1 files changed, 74 insertions, 0 deletions
diff --git a/js/seed/src/dev.js b/js/seed/src/dev.js
new file mode 100644
index 0000000..ee1a6e7
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+++ b/js/seed/src/dev.js
@@ -0,0 +1,74 @@
+// devMode.js
+// Minimal, single-file dev mode with scriptable console API
+
+/**
+ * Initialize dev mode: exposes a scriptable API for stepping through state history.
+ * @param {object} opts
+ * @param {function} opts.getState - returns current app state
+ * @param {function} opts.setState - sets app state
+ * @param {function} opts.render - triggers app re-render
+ */
+export function initDevMode({ getState, setState, render }) {
+  let history = [];
+  let pointer = -1;
+  let firstLoad = true;
+
+  function pushState(state) {
+    if (pointer < history.length - 1) history = history.slice(0, pointer + 1);
+    history.push(clone(state));
+    pointer = history.length - 1;
+    logInstructions();
+  }
+  function goTo(idx) {
+    if (idx < 0 || idx >= history.length) return;
+    pointer = idx;
+    setState(clone(history[pointer]));
+    render();
+    logInstructions();
+  }
+  function next() {
+    if (pointer < history.length - 1) goTo(pointer + 1);
+  }
+  function prev() {
+    if (pointer > 0) goTo(pointer - 1);
+  }
+  function get() {
+    return history[pointer];
+  }
+  function clone(obj) {
+    return JSON.parse(JSON.stringify(obj));
+  }
+  function table(obj) {
+    console.table(dev.history);
+  }
+  function logInstructions() {
+    if (firstLoad) {
+      console.log('[DevMode] State history debugger');
+      console.log('Usage:');
+      console.log('- dev.next()   // step forward');
+      console.log('- dev.prev()   // step backward');
+      console.log('- dev.goTo(n)  // jump to state n (1-based)');
+      console.log('- dev.get()    // get current state');
+      console.log('- dev.table()  // display history as a table');
+      console.log('- dev.history  // array of all states');
+      console.log('- dev.pointer  // current pointer (0-based)');
+      firstLoad = false;
+    }
+  }
+
+  // Expose API globally for console use
+  window.dev = {
+    next,
+    prev,
+    goTo,
+    get,
+    table,
+    get pointer() { return pointer; },
+    get history() { return history.slice(); },
+  };
+
+  // Initial state
+  pushState(getState());
+
+  return { pushState };
+} 
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