diff --git a/src/compile/data/facet.ts b/src/compile/data/facet.ts
index c5fb84b55a..0c678deeb1 100644
--- a/src/compile/data/facet.ts
+++ b/src/compile/data/facet.ts
@@ -213,7 +213,7 @@ export class FacetNode extends DataFlowNode {
     const hasSharedAxis: {row?: true; column?: true} = {};
     for (const headerChannel of HEADER_CHANNELS) {
       for (const headerType of HEADER_TYPES) {
-        const headers = (layoutHeaders[headerChannel] && layoutHeaders[headerChannel][headerType]) ?? [];
+        const headers = layoutHeaders[headerChannel]?.[headerType] ?? [];
         for (const header of headers) {
           if (header.axes?.length > 0) {
             hasSharedAxis[headerChannel] = true;
diff --git a/src/compile/selection/inputs.ts b/src/compile/selection/inputs.ts
index d34d1fb13a..992581ad7b 100644
--- a/src/compile/selection/inputs.ts
+++ b/src/compile/selection/inputs.ts
@@ -25,7 +25,7 @@ const inputBindings: SelectionCompiler<'point'> = {
     const name = selCmpt.name;
     const proj = selCmpt.project;
     const bind = selCmpt.bind;
-    const init = selCmpt.init && selCmpt.init[0]; // Can only exist on single selections (one initial value).
+    const init = selCmpt.init?.[0]; // Can only exist on single selections (one initial value).
     const datum = nearest.defined(selCmpt) ? '(item().isVoronoi ? datum.datum : datum)' : 'datum';
 
     proj.items.forEach((p, i) => {
diff --git a/src/compile/selection/interval.ts b/src/compile/selection/interval.ts
index 5ca5f400e0..aa71e151c2 100644
--- a/src/compile/selection/interval.ts
+++ b/src/compile/selection/interval.ts
@@ -61,7 +61,7 @@ const interval: SelectionCompiler<'interval'> = {
     const init = selCmpt.init ? selCmpt.init[0] : null;
 
     signals.push(
-      ...channels.reduce((arr, proj) => arr.concat(channelSignals(model, selCmpt, proj, init && init[proj.index])), [])
+      ...channels.reduce((arr, proj) => arr.concat(channelSignals(model, selCmpt, proj, init?.[proj.index])), [])
     );
 
     if (!model.hasProjection) {
@@ -119,10 +119,10 @@ const interval: SelectionCompiler<'interval'> = {
       const projection = stringValue(model.projectionName());
       const centerSg = model.projectionName() + CENTER;
       const {x, y} = selCmpt.project.hasChannel;
-      const xvname = x && x.signals.visual;
-      const yvname = y && y.signals.visual;
-      const xinit = x ? init && init[x.index] : `${centerSg}[0]`;
-      const yinit = y ? init && init[y.index] : `${centerSg}[1]`;
+      const xvname = x?.signals.visual;
+      const yvname = y?.signals.visual;
+      const xinit = x ? init?.[x.index] : `${centerSg}[0]`;
+      const yinit = y ? init?.[y.index] : `${centerSg}[1]`;
       const sizeSg = (layout: keyof LayoutSizeIndex) => model.getSizeSignalRef(layout).signal;
       const bbox =
         `[` +
diff --git a/src/compile/selection/translate.ts b/src/compile/selection/translate.ts
index 8431ae10b0..faefc23be0 100644
--- a/src/compile/selection/translate.ts
+++ b/src/compile/selection/translate.ts
@@ -83,8 +83,8 @@ function onDelta(
   const signal = signals.find(s => s.name === proj.signals[boundScales ? 'data' : 'visual']);
   const sizeSg = model.getSizeSignalRef(size).signal;
   const scaleCmpt = model.getScaleComponent(channel);
-  const scaleType = scaleCmpt && scaleCmpt.get('type');
-  const reversed = scaleCmpt && scaleCmpt.get('reverse'); // scale parsing sets this flag for fieldDef.sort
+  const scaleType = scaleCmpt?.get('type');
+  const reversed = scaleCmpt?.get('reverse'); // scale parsing sets this flag for fieldDef.sort
   const sign = !boundScales ? '' : channel === X ? (reversed ? '' : '-') : reversed ? '-' : '';
   const extent = `${anchor}.extent_${channel}`;
   const offset = `${sign}${delta}.${channel} / ${boundScales ? `${sizeSg}` : `span(${extent})`}`;
diff --git a/src/compile/selection/zoom.ts b/src/compile/selection/zoom.ts
index a326dd6969..680501324c 100644
--- a/src/compile/selection/zoom.ts
+++ b/src/compile/selection/zoom.ts
@@ -85,7 +85,7 @@ function onDelta(
   const signal = signals.find(s => s.name === proj.signals[boundScales ? 'data' : 'visual']);
   const sizeSg = model.getSizeSignalRef(size).signal;
   const scaleCmpt = model.getScaleComponent(channel);
-  const scaleType = scaleCmpt && scaleCmpt.get('type');
+  const scaleType = scaleCmpt?.get('type');
   const base = boundScales ? domain(model, channel) : signal.name;
   const delta = name + DELTA;
   const anchor = `${name}${ANCHOR}.${channel}`;
diff --git a/src/encoding.ts b/src/encoding.ts
index d37fbc74bb..e34ba7177a 100644
--- a/src/encoding.ts
+++ b/src/encoding.ts
@@ -337,7 +337,7 @@ export function channelHasField<F extends Field>(
   encoding: EncodingWithFacet<F>,
   channel: keyof EncodingWithFacet<F>
 ): boolean {
-  const channelDef = encoding && encoding[channel];
+  const channelDef = encoding?.[channel];
   if (channelDef) {
     if (isArray(channelDef)) {
       return some(channelDef, fieldDef => !!fieldDef.field);
@@ -352,7 +352,7 @@ export function channelHasFieldOrDatum<F extends Field>(
   encoding: EncodingWithFacet<F>,
   channel: keyof EncodingWithFacet<F>
 ): boolean {
-  const channelDef = encoding && encoding[channel];
+  const channelDef = encoding?.[channel];
   if (channelDef) {
     if (isArray(channelDef)) {
       return some(channelDef, fieldDef => !!fieldDef.field);
diff --git a/src/timeunit.ts b/src/timeunit.ts
index 0ef009371f..9c25f134af 100644
--- a/src/timeunit.ts
+++ b/src/timeunit.ts
@@ -149,7 +149,7 @@ export function isBinnedTimeUnit(
 }
 
 export function isBinnedTimeUnitString(timeUnit: TimeUnit | BinnedTimeUnit | undefined): timeUnit is BinnedTimeUnit {
-  return timeUnit && timeUnit.startsWith('binned');
+  return timeUnit?.startsWith('binned');
 }
 
 export const UTC_MULTI_TIMEUNIT_INDEX = {
diff --git a/src/util.ts b/src/util.ts
index 8c8be120fd..f618ef923b 100644
--- a/src/util.ts
+++ b/src/util.ts
@@ -484,7 +484,7 @@ export function stringify(data: any) {
   const seen: any[] = [];
 
   return (function _stringify(node: any) {
-    if (node && node.toJSON && typeof node.toJSON === 'function') {
+    if (node?.toJSON && typeof node.toJSON === 'function') {
       node = node.toJSON();
     }