TanStack · Sheraff · Sep 28, 2026 · Sep 28, 2026
diff --git a/.changeset/tidy-unobserved-atoms.md b/.changeset/tidy-unobserved-atoms.md
@@ -0,0 +1,5 @@
+---
+'@tanstack/store': patch
+---
+
+Allow computed atoms read without a subscription to be garbage collected while preserving cached snapshots and reconnecting dependencies when subscribed.
diff --git a/docs/reference/functions/batch.md b/docs/reference/functions/batch.md
@@ -7,7 +7,7 @@ title: batch
 function batch(fn): void;
 ```
 
-Defined in: [atom.ts:70](https://github.com/TanStack/store/blob/main/packages/store/src/atom.ts#L70)
+Defined in: [atom.ts:67](https://github.com/TanStack/store/blob/main/packages/store/src/atom.ts#L67)
 
 ## Parameters
 

diff --git a/docs/reference/functions/createAsyncAtom.md b/docs/reference/functions/createAsyncAtom.md
@@ -7,7 +7,7 @@ title: createAsyncAtom
 function createAsyncAtom<T>(getValue, options?): ReadonlyAtom<AsyncAtomState<T, unknown>>;
 ```
 
-Defined in: [atom.ts:108](https://github.com/TanStack/store/blob/main/packages/store/src/atom.ts#L108)
+Defined in: [atom.ts:121](https://github.com/TanStack/store/blob/main/packages/store/src/atom.ts#L121)
 
 ## Type Parameters
 

diff --git a/docs/reference/functions/createAtom.md b/docs/reference/functions/createAtom.md
@@ -9,7 +9,7 @@ title: createAtom
 function createAtom<T>(getValue, options?): ReadonlyAtom<T>;
 ```
 
-Defined in: [atom.ts:146](https://github.com/TanStack/store/blob/main/packages/store/src/atom.ts#L146)
+Defined in: [atom.ts:159](https://github.com/TanStack/store/blob/main/packages/store/src/atom.ts#L159)
 
 ### Type Parameters
 
@@ -37,7 +37,7 @@ Defined in: [atom.ts:146](https://github.com/TanStack/store/blob/main/packages/s
 function createAtom<T>(initialValue, options?): Atom<T>;
 ```
 
-Defined in: [atom.ts:150](https://github.com/TanStack/store/blob/main/packages/store/src/atom.ts#L150)
+Defined in: [atom.ts:163](https://github.com/TanStack/store/blob/main/packages/store/src/atom.ts#L163)
 
 ### Type Parameters
 

diff --git a/docs/reference/functions/flush.md b/docs/reference/functions/flush.md
@@ -7,7 +7,7 @@ title: flush
 function flush(): void;
 ```
 
-Defined in: [atom.ts:89](https://github.com/TanStack/store/blob/main/packages/store/src/atom.ts#L89)
+Defined in: [atom.ts:102](https://github.com/TanStack/store/blob/main/packages/store/src/atom.ts#L102)
 
 ## Returns
 

diff --git a/packages/store/src/alien.ts b/packages/store/src/alien.ts
@@ -57,62 +57,76 @@ export function createReactiveSystem({
     if (prevDep !== undefined && prevDep.dep === dep) {
       return
     }
-    const nextDep = prevDep !== undefined ? prevDep.nextDep : sub.deps
+    let nextDep = prevDep !== undefined ? prevDep.nextDep : sub.deps
+    const prevSub = dep.subsTail
     if (nextDep !== undefined && nextDep.dep === dep) {
       nextDep.version = version
       sub.depsTail = nextDep
-      return
-    }
-    const prevSub = dep.subsTail
-    if (
-      prevSub !== undefined &&
-      prevSub.version === version &&
-      prevSub.sub === sub
-    ) {
-      return
-    }
-    const newLink =
-      (sub.depsTail =
-      dep.subsTail =
-        {
-          version,
-          dep,
-          sub,
-          prevDep,
-          nextDep,
-          prevSub,
-          nextSub: undefined,
-        })
-    if (nextDep !== undefined) {
-      nextDep.prevDep = newLink
-    }
-    if (prevDep !== undefined) {
-      prevDep.nextDep = newLink
+      // A self pointer marks a retained link absent from the subscriber list.
+      if (nextDep.prevSub !== nextDep) {
+        return
+      }
     } else {
-      sub.deps = newLink
+      if (
+        prevSub !== undefined &&
+        prevSub.version === version &&
+        prevSub.sub === sub
+      ) {
+        return
+      }
+      const newLink = (sub.depsTail = {
+        version,
+        dep,
+        sub,
+        prevDep,
+        nextDep,
+        prevSub,
+        nextSub: undefined,
+      })
+      if (nextDep !== undefined) {
+        nextDep.prevDep = newLink
+      }
+      if (prevDep !== undefined) {
+        prevDep.nextDep = newLink
+      } else {
+        sub.deps = newLink
+      }
+      nextDep = newLink
     }
+    dep.subsTail = nextDep
+    nextDep.prevSub = prevSub
     if (prevSub !== undefined) {
-      prevSub.nextSub = newLink
+      prevSub.nextSub = nextDep
     } else {
-      dep.subs = newLink
+      dep.subs = nextDep
     }
   }
 
-  function unlink(link: Link, sub = link.sub): Link | undefined {
+  function unlink(
+    link: Link,
+    sub = link.sub,
+    keepDeps = false,
+  ): Link | undefined {
     const dep = link.dep
     const prevDep = link.prevDep
     const nextDep = link.nextDep
     const nextSub = link.nextSub
     const prevSub = link.prevSub
-    if (nextDep !== undefined) {
-      nextDep.prevDep = prevDep
-    } else {
-      sub.depsTail = prevDep
+    // Unobserved atoms retain their forward links for validation and reuse.
+    if (!keepDeps) {
+      if (nextDep !== undefined) {
+        nextDep.prevDep = prevDep
+      } else {
+        sub.depsTail = prevDep
+      }
+      if (prevDep !== undefined) {
+        prevDep.nextDep = nextDep
+      } else {
+        sub.deps = nextDep
+      }
     }
-    if (prevDep !== undefined) {
-      prevDep.nextDep = nextDep
-    } else {
-      sub.deps = nextDep
+    if (prevSub === link) {
+      return nextDep
     }
     if (nextSub !== undefined) {
       nextSub.prevSub = prevSub
@@ -124,6 +138,8 @@ export function createReactiveSystem({
     } else if ((dep.subs = nextSub) === undefined) {
       unwatched(dep)
     }
+    link.prevSub = link
+    link.nextSub = undefined
     return nextDep
   }
 

diff --git a/packages/store/src/atom.ts b/packages/store/src/atom.ts
@@ -8,7 +8,7 @@ import {
   createReactiveSystem,
 } from './alien'
 
-import type { ReactiveNode } from './alien'
+import type { Link, ReactiveNode } from './alien'
 import type {
   Atom,
   AtomOptions,
@@ -36,13 +36,16 @@ export function toObserver<T>(
 
 interface InternalAtom<T> extends ReactiveNode {
   _snapshot: T
+  _version: number
+  _unwatchedDeps?: boolean
   _update: (getValue?: T | ((snapshot: T) => T)) => boolean
   get: () => T
   subscribe: (observerOrFn: Observer<T> | ((value: T) => void)) => Subscription
 }
 
 const queuedEffects: Array<Effect | undefined> = []
 let cycle = 0
+let writeVersion = 0
 const { link, unlink, propagate, checkDirty, shallowPropagate } =
   createReactiveSystem({
     update(atom: InternalAtom<any>): boolean {
@@ -53,13 +56,7 @@ const { link, unlink, propagate, checkDirty, shallowPropagate } =
       queuedEffects[queuedEffectsLength++] = effect
       effect.flags &= ~WATCHING
     },
-    unwatched(atom: InternalAtom<any>): void {
-      if (atom.depsTail !== undefined) {
-        atom.depsTail = undefined
-        atom.flags = MUTABLE | DIRTY
-        purgeDeps(atom)
-      }
-    },
+    unwatched,
   })
 
 let notifyIndex = 0
@@ -86,6 +83,22 @@ function purgeDeps(sub: ReactiveNode) {
   }
 }
 
+function unwatched(atom: InternalAtom<any>): void {
+  if (atom.deps === undefined || atom._unwatchedDeps) {
+    return
+  }
+  atom._unwatchedDeps = true
+  // Preserve pending changes before replacing tracking cycles with snapshots
+  // of dependency versions. Detached nodes no longer receive invalidations.
+  if (atom.flags & PENDING) {
+    atom.flags = (atom.flags & ~PENDING) | DIRTY
+  }
+  for (let dep: Link | undefined = atom.deps; dep; dep = dep.nextDep) {
+    dep.version = (dep.dep as InternalAtom<any>)._version
+    unlink(dep, atom, true)
+  }
+}
+
 export function flush(): void {
   if (batchDepth > 0) {
     return
@@ -161,6 +174,7 @@ export function createAtom<T>(
   // Create plain object atom
   const atom: InternalAtom<T> = {
     _snapshot: isComputed ? undefined! : valueOrFn,
+    _version: 0,
 
     subs: undefined,
     subsTail: undefined,
@@ -200,6 +214,7 @@ export function createAtom<T>(
       const prevSub = activeSub
       const compare = options?.compare ?? Object.is
       if (isComputed) {
+        atom._unwatchedDeps = undefined
         activeSub = atom
         ++cycle
         atom.depsTail = undefined
@@ -221,9 +236,15 @@ export function createAtom<T>(
               : getValue!
         if (oldValue === undefined || !compare(oldValue, newValue)) {
           atom._snapshot = newValue
+          atom._version = ++writeVersion
           return true
         }
         return false
+      } catch (error) {
+        if (isComputed) {
+          atom.flags |= DIRTY
+        }
+        throw error
       } finally {
         activeSub = prevSub
         if (isComputed) {
@@ -235,23 +256,69 @@ export function createAtom<T>(
   }
 
   if (isComputed) {
+    let checkedVersion = -1
     atom.flags = MUTABLE | DIRTY
     atom.get = function (): T {
-      const flags = atom.flags
-      if (flags & DIRTY || (flags & PENDING && checkDirty(atom.deps!, atom))) {
-        if (atom._update()) {
-          const subs = atom.subs
-          if (subs !== undefined) {
-            shallowPropagate(subs)
+      try {
+        const deps = atom._unwatchedDeps && atom.deps
+        if (
+          deps &&
+          !(atom.flags & DIRTY) &&
+          (activeSub !== undefined || checkedVersion !== writeVersion)
+        ) {
+          const prevSub = activeSub
+          // Subscribing reconnects the cached dependencies without changing the
+          // snapshot. An untracked read validates them without retaining links.
+          activeSub = prevSub === undefined ? undefined : atom
+          if (activeSub !== undefined) {
+            atom._unwatchedDeps = undefined
+            atom.depsTail = undefined
+          }
+          try {
+            for (
+              let depLink: Link | undefined = deps;
+              depLink;
+              depLink = depLink.nextDep
+            ) {
+              const dep = depLink.dep as InternalAtom<any>
+              const version = depLink.version
+              dep.get()
+              if (dep._version !== version) {
+                atom.flags |= DIRTY
+                break
+              }
+            }
+          } finally {
+            activeSub = prevSub
           }
         }
-      } else if (flags & PENDING) {
-        atom.flags = flags & ~PENDING
-      }
-      if (activeSub !== undefined) {
-        link(atom, activeSub, cycle)
+        const flags = atom.flags
+        if (
+          flags & DIRTY ||
+          (flags & PENDING && checkDirty(atom.deps!, atom))
+        ) {
+          if (atom._update()) {
+            const subs = atom.subs
+            if (subs !== undefined) {
+              shallowPropagate(subs)
+            }
+          }
+        } else if (flags & PENDING) {
+          atom.flags = flags & ~PENDING
+        }
+        if (activeSub !== undefined) {
+          link(atom, activeSub, cycle)
+        }
+        checkedVersion = writeVersion
+        return atom._snapshot
+      } catch (error) {
+        atom.flags |= DIRTY
+        throw error
+      } finally {
+        if (atom.subs === undefined) {
+          unwatched(atom)
+        }
       }
-      return atom._snapshot
     }
   } else {
     ;(atom as unknown as Atom<T>).set = function (