fix: keep valid setData on a no-copy fast path

packages/chart/src/core/chart.ts

@@ -390,7 +390,7 @@ export class Chart {
     } else {
       throw new Error('chart-ts: inject a container canvas or a ChartDocument');
     }
-    this.store.setData(this.config.data);
+    this.store.setData(this.config.data.slice());
     this.timeSlots.sync(this.store.raw(), this.config.timeScale, 'data');
     this.syncInlineBook();
     this.syncHeatmap();
@@ -452,7 +452,7 @@ export class Chart {
   setData(candles: readonly Candle[]): void {
     this.rangeAnimation?.clear();
     this.candleAnimation?.clear();
-    this.store.setData(candles);
+    this.store.setData(candles.slice());
     this.timeSlots.sync(this.store.raw(), this.config.timeScale, 'data');
     this.events.dataLoaded('set', this.store.length);
     this.indicatorCache.clear();
@@ -577,7 +577,7 @@ export class Chart {
     if (partial.data !== undefined) {
       this.rangeAnimation?.clear();
       this.candleAnimation?.clear();
-      this.store.setData(this.config.data);
+      this.store.setData(this.config.data.slice());
       this.events.dataLoaded('set', this.store.length);
       this.indicatorCache.clear();
     }

packages/chart/src/core/data.ts

@@ -150,11 +150,16 @@ export class DataStore {
   /**
    * Replaces the whole dataset. Non-finite rows are dropped, duplicate times
    * keep the last row, `high`/`low` expand to cover `open` and `close`, and a
-   * negative or non-finite volume becomes 0. Already-clean input keeps the
-   * same candle objects.
+   * negative or non-finite volume becomes 0. An array that is already finite,
+   * strictly increasing, unique and OHLC-consistent is stored as-is: no copy.
+   * Callers must not mutate that array.
    */
   setData(candles: readonly Candle[]): void {
-    this.candles = firstDirty(candles) === candles.length ? candles.slice() : sanitizeCandles(candles);
+    if (firstDirty(candles) === candles.length) {
+      this.candles = candles as Candle[];
+      return;
+    }
+    this.candles = sanitizeCandles(candles);
   }
 
   /**

packages/chart/test/data.test.ts

@@ -16,13 +16,17 @@ describe('DataStore', () => {
     assert.equal(s.last(), undefined);
     assert.deepEqual(s.all(), []);
   });
-  it('setData sorts defensively and copies', () => {
+  it('setData sorts defensively and copies only when a row is dirty', () => {
     const s = new DataStore();
     const input = [candle(3), candle(1), candle(2)];
     s.setData(input);
     assert.deepEqual(s.all().map((c) => c.time), [1, 2, 3]);
     input.push(candle(9));
     assert.equal(s.length, 3);
+    const clean = [candle(1), candle(2), candle(3)];
+    s.setData(clean);
+    assert.equal(s.raw(), clean);
+    assert.equal(s.at(0), clean[0]);
   });
   it('append inserts in order and out of order', () => {
     const s = new DataStore();