init claude-code

ink/optimizer.ts

@@ -0,0 +1,93 @@
+import type { Diff } from './frame.js'
+
+/**
+ * Optimize a diff by applying all optimization rules in a single pass.
+ * This reduces the number of patches that need to be written to the terminal.
+ *
+ * Rules applied:
+ * - Remove empty stdout patches
+ * - Merge consecutive cursorMove patches
+ * - Remove no-op cursorMove (0,0) patches
+ * - Concat adjacent style patches (transition diffs — can't drop either)
+ * - Dedupe consecutive hyperlinks with same URI
+ * - Cancel cursor hide/show pairs
+ * - Remove clear patches with count 0
+ */
+export function optimize(diff: Diff): Diff {
+  if (diff.length <= 1) {
+    return diff
+  }
+
+  const result: Diff = []
+  let len = 0
+
+  for (const patch of diff) {
+    const type = patch.type
+
+    // Skip no-ops
+    if (type === 'stdout') {
+      if (patch.content === '') continue
+    } else if (type === 'cursorMove') {
+      if (patch.x === 0 && patch.y === 0) continue
+    } else if (type === 'clear') {
+      if (patch.count === 0) continue
+    }
+
+    // Try to merge with previous patch
+    if (len > 0) {
+      const lastIdx = len - 1
+      const last = result[lastIdx]!
+      const lastType = last.type
+
+      // Merge consecutive cursorMove
+      if (type === 'cursorMove' && lastType === 'cursorMove') {
+        result[lastIdx] = {
+          type: 'cursorMove',
+          x: last.x + patch.x,
+          y: last.y + patch.y,
+        }
+        continue
+      }
+
+      // Collapse consecutive cursorTo (only the last one matters)
+      if (type === 'cursorTo' && lastType === 'cursorTo') {
+        result[lastIdx] = patch
+        continue
+      }
+
+      // Concat adjacent style patches. styleStr is a transition diff
+      // (computed by diffAnsiCodes(from, to)), not a setter — dropping
+      // the first is only sound if its undo-codes are a subset of the
+      // second's, which is NOT guaranteed. e.g. [\e[49m, \e[2m]: dropping
+      // the bg reset leaks it into the next \e[2J/\e[2K via BCE.
+      if (type === 'styleStr' && lastType === 'styleStr') {
+        result[lastIdx] = { type: 'styleStr', str: last.str + patch.str }
+        continue
+      }
+
+      // Dedupe hyperlinks
+      if (
+        type === 'hyperlink' &&
+        lastType === 'hyperlink' &&
+        patch.uri === last.uri
+      ) {
+        continue
+      }
+
+      // Cancel cursor hide/show pairs
+      if (
+        (type === 'cursorShow' && lastType === 'cursorHide') ||
+        (type === 'cursorHide' && lastType === 'cursorShow')
+      ) {
+        result.pop()
+        len--
+        continue
+      }
+    }
+
+    result.push(patch)
+    len++
+  }
+
+  return result
+}