diff --git a/src/Chart.ts b/src/Chart.ts
index 5e8300f7..2dd47c15 100644
--- a/src/Chart.ts
+++ b/src/Chart.ts
@@ -47,7 +47,7 @@ import SeparatorPane from './pane/SeparatorPane'
 import { type PaneOptions, PanePosition, PANE_DEFAULT_HEIGHT, PaneIdConstants, PaneState, PANE_MIN_HEIGHT } from './pane/types'
 
 import type AxisImp from './component/Axis'
-import { AxisPosition, type Axis } from './component/Axis'
+import { AxisPosition } from './component/Axis'
 
 import type { IndicatorFilter, Indicator, IndicatorCreate } from './component/Indicator'
 import type { OverlayFilter, Overlay, OverlayCreate } from './component/Overlay'
@@ -243,8 +243,8 @@ export default class ChartImp implements Chart {
           const p = this._drawPanes[i]
           const prevP = this._drawPanes[i - 1]
           if (
-            p?.getOptions().position === PanePosition.Bottom &&
-            prevP?.getOptions().position !== PanePosition.Bottom
+            p.getOptions().position === PanePosition.Bottom &&
+            prevP.getOptions().position !== PanePosition.Bottom
           ) {
             pane = new DrawPaneClass(this._chartContainer, p.getContainer(), this, id, options ?? {})
             index = i
@@ -393,7 +393,7 @@ export default class ChartImp implements Chart {
     this._drawPanes.forEach(pane => {
       if (pane.getId() !== PaneIdConstants.X_AXIS) {
         const yAxis = pane.getAxisComponent() as YAxis
-        const inside = yAxis.inside ?? false
+        const inside = yAxis.inside
         const yAxisWidth = yAxis.getAutoSize()
         if (yAxis.position === AxisPosition.Left) {
           leftYAxisWidth = Math.max(leftYAxisWidth, yAxisWidth)
@@ -412,11 +412,13 @@ export default class ChartImp implements Chart {
     let mainWidth = totalWidth
     let mainLeft = 0
     let mainRight = 0
+    // eslint-disable-next-line @typescript-eslint/no-unnecessary-condition
     if (leftYAxisOutside) {
       mainWidth -= leftYAxisWidth
       mainLeft = leftYAxisWidth
     }
 
+    // eslint-disable-next-line @typescript-eslint/no-unnecessary-condition
     if (rightYAxisOutside) {
       mainWidth -= rightYAxisWidth
       mainRight = rightYAxisWidth
@@ -474,7 +476,7 @@ export default class ChartImp implements Chart {
     }
   }
 
-  getDrawPaneById (paneId: string): Nullable<DrawPane<Axis>> {
+  getDrawPaneById (paneId: string): Nullable<DrawPane> {
     if (paneId === PaneIdConstants.CANDLE) {
       return this._candlePane
     }
@@ -519,7 +521,7 @@ export default class ChartImp implements Chart {
     if (forceMeasureWidth) {
       this._measurePaneWidth()
     }
-    if (shouldUpdate ?? false) {
+    if (shouldUpdate) {
       (this._xAxisPane.getAxisComponent() as unknown as AxisImp).buildTicks(true)
       this.updatePane(UpdateLevel.All)
     }
@@ -718,7 +720,7 @@ export default class ChartImp implements Chart {
     if (currentPane !== null) {
       const result = this._chartStore.addIndicator(indicator, paneId ?? '', isStack ?? false)
       if (result) {
-        this._setPaneOptions(paneOptions ?? {}, (currentPane.getAxisComponent() as AxisImp).buildTicks(true) ?? false)
+        this._setPaneOptions(paneOptions ?? {}, (currentPane.getAxisComponent() as AxisImp).buildTicks(true))
       }
     } else {
       paneId ??= createId(PaneIdConstants.INDICATOR)
@@ -764,7 +766,7 @@ export default class ChartImp implements Chart {
             shouldMeasureHeight = true
             const separatorPane = this._separatorPanes.get(pane)
             if (isValid(separatorPane)) {
-              const topPane = separatorPane?.getTopPane()
+              const topPane = separatorPane.getTopPane()
               for (const item of this._separatorPanes) {
                 if (item[1].getTopPane().getId() === paneId) {
                   item[1].setTopPane(topPane)
@@ -941,10 +943,10 @@ export default class ChartImp implements Chart {
             dataIndex = this._chartStore.timestampToDataIndex(point.timestamp)
           }
           if (isNumber(dataIndex)) {
-            coordinate.x = xAxis?.convertToPixel(dataIndex)
+            coordinate.x = xAxis.convertToPixel(dataIndex)
           }
           if (isNumber(point.value)) {
-            const y = yAxis?.convertToPixel(point.value)
+            const y = yAxis.convertToPixel(point.value)
             coordinate.y = absolute ? bounding.top + y : y
           }
           return coordinate
@@ -967,7 +969,7 @@ export default class ChartImp implements Chart {
         points = cs.map(coordinate => {
           const point: Partial<Point> = {}
           if (isNumber(coordinate.x)) {
-            const dataIndex = xAxis?.convertFromPixel(coordinate.x) ?? -1
+            const dataIndex = xAxis.convertFromPixel(coordinate.x)
             point.dataIndex = dataIndex
             point.timestamp = this._chartStore.dataIndexToTimestamp(dataIndex) ?? undefined
           }
diff --git a/src/Event.ts b/src/Event.ts
index 62148052..19247251 100644
--- a/src/Event.ts
+++ b/src/Event.ts
@@ -18,6 +18,7 @@ import type Coordinate from './common/Coordinate'
 import { UpdateLevel } from './common/Updater'
 import type Crosshair from './common/Crosshair'
 import { requestAnimationFrame, cancelAnimationFrame } from './common/utils/compatible'
+import { isValid } from './common/utils/typeChecks'
 
 import type { AxisRange } from './component/Axis'
 import type YAxis from './component/YAxis'
@@ -154,8 +155,8 @@ export default class Event implements EventHandler {
           return widget.dispatchEvent('mouseDownEvent', event)
         }
         case WidgetNameConstants.MAIN: {
-          const range = (pane as DrawPane<YAxis>).getAxisComponent().getRange() ?? null
-          this._prevYAxisRange = range === null ? range : { ...range }
+          const range = (pane as DrawPane<YAxis>).getAxisComponent().getRange()
+          this._prevYAxisRange = { ...range }
           this._startScrollCoordinate = { x: event.x, y: event.y }
           this._chart.getChartStore().startScroll()
           return widget.dispatchEvent('mouseDownEvent', event)
@@ -174,8 +175,8 @@ export default class Event implements EventHandler {
           if (consumed) {
             this._chart.updatePane(UpdateLevel.Overlay)
           }
-          const range = (pane as DrawPane<YAxis>).getAxisComponent().getRange() ?? null
-          this._prevYAxisRange = range === null ? range : { ...range }
+          const range = (pane as DrawPane<YAxis>).getAxisComponent().getRange()
+          this._prevYAxisRange = { ...range }
           this._yAxisStartScaleDistance = event.pageY
           return consumed
         }
@@ -204,9 +205,7 @@ export default class Event implements EventHandler {
           let crosshair: Crosshair | undefined = { x: event.x, y: event.y, paneId: pane?.getId() }
           if (consumed && chartStore.getActiveTooltipIcon() !== null) {
             crosshair = undefined
-            if (widget !== null) {
-              widget.getContainer().style.cursor = 'pointer'
-            }
+            widget.getContainer().style.cursor = 'pointer'
           }
           this._chart.getChartStore().setCrosshair(crosshair)
           return consumed
@@ -279,7 +278,7 @@ export default class Event implements EventHandler {
           const consumed = widget.dispatchEvent('pressedMouseMoveEvent', event)
           if (!consumed) {
             const xAxis = (pane as DrawPane<XAxis>).getAxisComponent()
-            if ((xAxis?.scrollZoomEnabled ?? true)) {
+            if ((xAxis.scrollZoomEnabled)) {
               const scale = this._xAxisStartScaleDistance / event.pageX
               if (Number.isFinite(scale)) {
                 const zoomScale = (scale - this._xAxisScale) * 10
@@ -632,7 +631,7 @@ export default class Event implements EventHandler {
     }
     let widget: Nullable<Widget> = null
     if (pane !== null) {
-      if (widget === null) {
+      if (!isValid(widget)) {
         const mainWidget = pane.getMainWidget()
         const mainBounding = mainWidget.getBounding()
         if (
@@ -642,7 +641,7 @@ export default class Event implements EventHandler {
           widget = mainWidget
         }
       }
-      if (widget === null) {
+      if (!isValid(widget)) {
         const yAxisWidget = pane.getYAxisWidget()
         if (yAxisWidget !== null) {
           const yAxisBounding = yAxisWidget.getBounding()
diff --git a/src/Store.ts b/src/Store.ts
index 12a0bf8e..93bd1a02 100644
--- a/src/Store.ts
+++ b/src/Store.ts
@@ -453,6 +453,7 @@ export default class Store {
                   point.dataIndex = point.dataIndex + dataLengthChange
                 }
                 const data = this._dataList[point.dataIndex]
+                // eslint-disable-next-line @typescript-eslint/no-unnecessary-condition
                 point.timestamp = data?.timestamp
               }
             })
@@ -838,7 +839,7 @@ export default class Store {
     }
     let zoomCoordinate: Nullable<Partial<Coordinate>> = coordinate ?? null
     if (!isNumber(zoomCoordinate?.x)) {
-      zoomCoordinate = { x: this._crosshair?.x ?? this._totalBarSpace / 2 }
+      zoomCoordinate = { x: this._crosshair.x ?? this._totalBarSpace / 2 }
     }
     const x = zoomCoordinate.x!
     const floatIndex = this.coordinateToFloatIndex(x)
@@ -900,7 +901,7 @@ export default class Store {
     if (
       prevCrosshair.x !== cr.x || prevCrosshair.y !== cr.y || prevCrosshair.paneId !== cr.paneId
     ) {
-      if (kLineData !== null) {
+      if (isValid(kLineData)) {
         this._chart.crosshairChange(this._crosshair)
       }
       if (!(notInvalidate ?? false)) {
@@ -1128,6 +1129,7 @@ export default class Store {
         }
       }
     })
+    // eslint-disable-next-line @typescript-eslint/no-unnecessary-condition
     if (sortFlag) {
       this._sortIndicators()
     }
@@ -1194,7 +1196,7 @@ export default class Store {
       if (isValid(create.id)) {
         let findOverlay: Nullable<OverlayImp> = null
         for (const [, overlays] of this._overlays) {
-          const overlay = overlays.find(o => o.id === overlay.id)
+          const overlay = overlays.find(o => o.id === create.id)
           if (isValid(overlay)) {
             findOverlay = overlay
             break
@@ -1208,6 +1210,7 @@ export default class Store {
       if (isValid(OverlayClazz)) {
         const id = create.id ?? createId(OVERLAY_ID_PREFIX)
         const overlay = new OverlayClazz()
+        // eslint-disable-next-line @typescript-eslint/no-unnecessary-condition
         const groupId = overlay.groupId ?? id
         create.id = id
         create.groupId = groupId
@@ -1289,6 +1292,7 @@ export default class Store {
       })
     })
 
+    // eslint-disable-next-line @typescript-eslint/no-unnecessary-condition
     if (sortFlag) {
       this._sortOverlays()
     }
@@ -1353,16 +1357,16 @@ export default class Store {
         let sortFlag = false
         if (overlay !== null) {
           sortFlag = true
-          if (isFunction(overlay?.onMouseLeave)) {
-            overlay?.onMouseLeave({ overlay, figureKey, figureIndex, ...event })
+          if (isFunction(overlay.onMouseLeave)) {
+            overlay.onMouseLeave({ overlay, figureKey, figureIndex, ...event })
             ignoreUpdateFlag = true
           }
         }
 
         if (infoOverlay !== null) {
           sortFlag = true
-          if (isFunction(infoOverlay?.onMouseEnter)) {
-            infoOverlay?.onMouseEnter({ overlay: infoOverlay, figureKey: info.figureKey, figureIndex: info.figureIndex, ...event })
+          if (isFunction(infoOverlay.onMouseEnter)) {
+            infoOverlay.onMouseEnter({ overlay: infoOverlay, figureKey: info.figureKey, figureIndex: info.figureIndex, ...event })
             ignoreUpdateFlag = true
           }
         }
@@ -1409,7 +1413,7 @@ export default class Store {
   }
 
   isOverlayDrawing (): boolean {
-    return this._progressOverlayInfo !== null && (this._progressOverlayInfo?.overlay.isDrawing() ?? false)
+    return this._progressOverlayInfo?.overlay.isDrawing() ?? false
   }
 
   clear (): void {
diff --git a/src/common/utils/format.ts b/src/common/utils/format.ts
index f5f97491..b1422269 100644
--- a/src/common/utils/format.ts
+++ b/src/common/utils/format.ts
@@ -92,6 +92,7 @@ export function formatDateToDateTime (dateTimeFormat: Intl.DateTimeFormat, times
 
 export function formatDateToString (dateTimeFormat: Intl.DateTimeFormat, timestamp: number, format: string): string {
   const date = formatDateToDateTime(dateTimeFormat, timestamp)
+  // eslint-disable-next-line @typescript-eslint/no-unsafe-return
   return format.replace(/YYYY|MM|DD|HH|mm|ss/g, key => date[key])
 }
 
diff --git a/src/common/utils/platform.ts b/src/common/utils/platform.ts
index 3dcdf2f6..5c7e7eeb 100644
--- a/src/common/utils/platform.ts
+++ b/src/common/utils/platform.ts
@@ -16,13 +16,12 @@ export function isFF (): boolean {
   if (typeof window === 'undefined') {
     return false
   }
-  return (window.navigator.userAgent.toLowerCase().indexOf('firefox') ?? -1) > -1
+  return window.navigator.userAgent.toLowerCase().includes('firefox')
 }
 
 export function isIOS (): boolean {
   if (typeof window === 'undefined') {
     return false
   }
-  // eslint-disable-next-line @typescript-eslint/no-deprecated
-  return /iPhone|iPad|iPod/.test(window.navigator.platform)
+  return /iPhone|iPad|iPod|iOS/.test(window.navigator.userAgent)
 }
diff --git a/src/common/utils/typeChecks.ts b/src/common/utils/typeChecks.ts
index 37fffcae..0912bece 100644
--- a/src/common/utils/typeChecks.ts
+++ b/src/common/utils/typeChecks.ts
@@ -19,7 +19,9 @@ export function merge (target: any, source: any): void {
   }
   for (const key in source) {
     if (Object.prototype.hasOwnProperty.call(source, key) as boolean) {
+      // eslint-disable-next-line @typescript-eslint/no-unsafe-assignment, @typescript-eslint/no-unsafe-member-access
       const targetProp = target[key]
+      // eslint-disable-next-line @typescript-eslint/no-unsafe-assignment, @typescript-eslint/no-unsafe-member-access
       const sourceProp = source[key]
       if (
         isObject(sourceProp) &&
@@ -27,7 +29,9 @@ export function merge (target: any, source: any): void {
       ) {
         merge(targetProp, sourceProp)
       } else {
+        // eslint-disable-next-line @typescript-eslint/no-unsafe-member-access
         if (isValid(source[key])) {
+          // eslint-disable-next-line @typescript-eslint/no-unsafe-assignment, @typescript-eslint/no-unsafe-member-access
           target[key] = clone(source[key])
         }
       }
@@ -51,12 +55,15 @@ export function clone<T> (target: T): T {
     if (Object.prototype.hasOwnProperty.call(target, key) as boolean) {
       const v = target[key]
       if (isObject(v)) {
+        // eslint-disable-next-line @typescript-eslint/no-unsafe-member-access
         copy[key] = clone(v)
       } else {
+        // eslint-disable-next-line @typescript-eslint/no-unsafe-member-access
         copy[key] = v
       }
     }
   }
+  // eslint-disable-next-line @typescript-eslint/no-unsafe-return
   return copy
 }
 
@@ -64,6 +71,7 @@ export function isArray<T = unknown> (value: unknown): value is T[] {
   return Object.prototype.toString.call(value) === '[object Array]'
 }
 
+// eslint-disable-next-line @typescript-eslint/no-unnecessary-type-parameters
 export function isFunction<T = (...args: unknown[]) => unknown> (value: unknown): value is T {
   return typeof value === 'function'
 }
diff --git a/src/extension/figure/rect.ts b/src/extension/figure/rect.ts
index 78c6ee4e..cdcdefa7 100644
--- a/src/extension/figure/rect.ts
+++ b/src/extension/figure/rect.ts
@@ -60,7 +60,7 @@ export function drawRect (ctx: CanvasRenderingContext2D, attrs: RectAttrs | Rect
     borderRadius: r = 0,
     borderDashedValue = [2, 2]
   } = styles
-  // eslint-disable-next-line @typescript-eslint/unbound-method
+  // eslint-disable-next-line @typescript-eslint/unbound-method, @typescript-eslint/no-unnecessary-condition
   const draw = ctx.roundRect ?? ctx.rect
   const solid = (style === PolygonType.Fill || styles.style === PolygonType.StrokeFill) && (!isString(color) || !isTransparent(color))
   if (solid) {
diff --git a/src/extension/i18n/index.ts b/src/extension/i18n/index.ts
index b066a56c..34dc9de3 100644
--- a/src/extension/i18n/index.ts
+++ b/src/extension/i18n/index.ts
@@ -31,6 +31,7 @@ function getSupportedLocales (): string[] {
 }
 
 function i18n (key: string, locale: string): string {
+  // eslint-disable-next-line @typescript-eslint/no-unnecessary-condition
   return locales[locale]?.[key] ?? key
 }
 
diff --git a/src/extension/indicator/averagePrice.ts b/src/extension/indicator/averagePrice.ts
index 41b0de68..e9e78b98 100644
--- a/src/extension/indicator/averagePrice.ts
+++ b/src/extension/indicator/averagePrice.ts
@@ -35,8 +35,8 @@ const averagePrice: IndicatorTemplate<Avp> = {
     let totalVolume = 0
     return dataList.map((kLineData: KLineData) => {
       const avp: Avp = {}
-      const turnover = kLineData?.turnover ?? 0
-      const volume = kLineData?.volume ?? 0
+      const turnover = kLineData.turnover ?? 0
+      const volume = kLineData.volume ?? 0
       totalTurnover += turnover
       totalVolume += volume
       if (totalVolume !== 0) {
diff --git a/src/extension/indicator/stopAndReverse.ts b/src/extension/indicator/stopAndReverse.ts
index 1615462f..1943002e 100644
--- a/src/extension/indicator/stopAndReverse.ts
+++ b/src/extension/indicator/stopAndReverse.ts
@@ -38,7 +38,7 @@ const stopAndReverse: IndicatorTemplate<Sar> = {
         const { current } = data
         const sar = current.indicatorData?.sar ?? Number.MIN_SAFE_INTEGER
         const kLineData = current.kLineData!
-        const halfHL = (kLineData?.high + kLineData?.low) / 2
+        const halfHL = (kLineData.high + kLineData.low) / 2
         const color = sar < halfHL
           ? formatValue(indicator.styles, 'circles[0].upColor', (defaultStyles.circles)[0].upColor) as string
           : formatValue(indicator.styles, 'circles[0].downColor', (defaultStyles.circles)[0].downColor) as string
diff --git a/src/extension/overlay/simpleAnnotation.ts b/src/extension/overlay/simpleAnnotation.ts
index 451d00f9..2417bd93 100644
--- a/src/extension/overlay/simpleAnnotation.ts
+++ b/src/extension/overlay/simpleAnnotation.ts
@@ -48,7 +48,7 @@ const simpleAnnotation: OverlayTemplate = {
       },
       {
         type: 'text',
-        attrs: { x: startX, y: arrowEndY, text: text ?? '', align: 'center', baseline: 'bottom' },
+        attrs: { x: startX, y: arrowEndY, text, align: 'center', baseline: 'bottom' },
         ignoreEvent: true
       }
     ]
diff --git a/src/extension/overlay/simpleTag.ts b/src/extension/overlay/simpleTag.ts
index bfa15fe9..f599ee30 100644
--- a/src/extension/overlay/simpleTag.ts
+++ b/src/extension/overlay/simpleTag.ts
@@ -60,7 +60,7 @@ const simpleTag: OverlayTemplate = {
     if (!isValid(text) && isNumber(overlay.points[0].value)) {
       text = formatPrecision(overlay.points[0].value, precision.price)
     }
-    return { type: 'text', attrs: { x, y: coordinates[0].y, text: text ?? '', align: textAlign, baseline: 'middle' } }
+    return { type: 'text', attrs: { x, y: coordinates[0].y, text, align: textAlign, baseline: 'middle' } }
   }
 }