diff --git a/Project.toml b/Project.toml
index b1326a1..028d514 100644
--- a/Project.toml
+++ b/Project.toml
@@ -1,7 +1,7 @@
 name = "ITensorBase"
 uuid = "4795dd04-0d67-49bb-8f44-b89c448a1dc7"
 authors = ["ITensor developers <support@itensor.org> and contributors"]
-version = "0.1.13"
+version = "0.1.14"
 
 [deps]
 Accessors = "7d9f7c33-5ae7-4f3b-8dc6-eff91059b697"
@@ -16,9 +16,11 @@ VectorInterface = "409d34a3-91d5-4945-b6ec-7529ddf182d8"
 
 [weakdeps]
 DiagonalArrays = "74fd4be6-21e2-4f6f-823a-4360d37c7a77"
+SparseArraysBase = "0d5efcca-f356-4864-8770-e1ed8d78f208"
 
 [extensions]
 ITensorBaseDiagonalArraysExt = "DiagonalArrays"
+ITensorBaseSparseArraysBaseExt = ["NamedDimsArrays", "SparseArraysBase"]
 
 [compat]
 Accessors = "0.1.39"
@@ -28,6 +30,7 @@ FillArrays = "1.13.0"
 LinearAlgebra = "1.10"
 MapBroadcast = "0.1.5"
 NamedDimsArrays = "0.4"
+SparseArraysBase = "0.2.11"
 UnallocatedArrays = "0.1.1"
 UnspecifiedTypes = "0.1.1"
 VectorInterface = "0.5.0"
diff --git a/ext/ITensorBaseSparseArraysBaseExt/ITensorBaseSparseArraysBaseExt.jl b/ext/ITensorBaseSparseArraysBaseExt/ITensorBaseSparseArraysBaseExt.jl
new file mode 100644
index 0000000..e8eb709
--- /dev/null
+++ b/ext/ITensorBaseSparseArraysBaseExt/ITensorBaseSparseArraysBaseExt.jl
@@ -0,0 +1,13 @@
+module ITensorBaseSparseArraysBaseExt
+
+using ITensorBase: ITensor, Index
+using NamedDimsArrays: dename
+using SparseArraysBase: SparseArraysBase, oneelement
+
+function SparseArraysBase.oneelement(
+  value, index::NTuple{N,Int}, ax::NTuple{N,Index}
+) where {N}
+  return ITensor(oneelement(value, index, only.(axes.(dename.(ax)))), ax)
+end
+
+end
diff --git a/src/quirks.jl b/src/quirks.jl
index 7cd48e5..e290280 100644
--- a/src/quirks.jl
+++ b/src/quirks.jl
@@ -1,32 +1,31 @@
 # TODO: Define this properly.
+# TODO: Rename this to `dual`.
 dag(i::Index) = i
 # TODO: Define this properly.
+# TODO: Rename this to `dual`.
 dag(a::ITensor) = a
-# TODO: Deprecate.
+
+# TODO: Deprecate, just use `Int(length(i))` or
+# `unname(length(i))` directly.
 # Conversion to `Int` is used in case the output is named.
 dim(i::Index) = Int(length(i))
 # TODO: Deprecate.
 # Conversion to `Int` is used in case the output is named.
+# TODO: Deprecate, just use `Int(length(i))` or
+# `unname(length(i))` directly.
 dim(a::AbstractITensor) = Int(length(a))
+
 # TODO: Define this properly.
-hasqns(i::Index) = false
+# TODO: Maybe rename to `isgraded(i::Index) = isgraded(dename(i))`.
+hasqns(::Index) = false
 # TODO: Define this properly.
-hasqns(i::AbstractITensor) = false
+# TODO: Maybe rename to `isgraded(a) = all(isgraded, axes(a))`.
+hasqns(::AbstractITensor) = false
 
 # This seems to be needed to get broadcasting working.
 # TODO: Investigate this and see if we can get rid of it.
 Base.Broadcast.extrude(a::AbstractITensor) = a
 
-# TODO: Generalize this.
-# Maybe define it as `oneelement`, and base it on
-# `FillArrays.OneElement` (https://juliaarrays.github.io/FillArrays.jl/stable/#FillArrays.OneElement).
-function onehot(elt::Type{<:Number}, iv::Pair{<:Index,<:Int})
-  a = ITensor(first(iv))
-  a[last(iv)] = one(elt)
-  return a
-end
-onehot(iv::Pair{<:Index,<:Int}) = onehot(Bool, iv)
-
 # TODO: This is just a stand-in for truncated SVD
 # that only makes use of `maxdim`, just to get some
 # functionality running in `ITensorMPS.jl`.
diff --git a/test/Project.toml b/test/Project.toml
index 355bb50..fce2cd3 100644
--- a/test/Project.toml
+++ b/test/Project.toml
@@ -5,6 +5,7 @@ ITensorBase = "4795dd04-0d67-49bb-8f44-b89c448a1dc7"
 LinearAlgebra = "37e2e46d-f89d-539d-b4ee-838fcccc9c8e"
 NamedDimsArrays = "60cbd0c0-df58-4cb7-918c-6f5607b73fde"
 SafeTestsets = "1bc83da4-3b8d-516f-aca4-4fe02f6d838f"
+SparseArraysBase = "0d5efcca-f356-4864-8770-e1ed8d78f208"
 Suppressor = "fd094767-a336-5f1f-9728-57cf17d0bbfb"
 Test = "8dfed614-e22c-5e08-85e1-65c5234f0b40"
 
diff --git a/test/test_basics.jl b/test/test_basics.jl
index c2c0e1b..b19c892 100644
--- a/test/test_basics.jl
+++ b/test/test_basics.jl
@@ -2,6 +2,7 @@ using ITensorBase:
   ITensorBase, ITensor, Index, gettag, hastag, inds, plev, prime, settag, tags, unsettag
 using DiagonalArrays: δ, delta, diagview
 using NamedDimsArrays: dename, name, named
+using SparseArraysBase: oneelement
 using Test: @test, @test_broken, @testset
 
 @testset "ITensorBase" begin
@@ -53,4 +54,25 @@ using Test: @test, @test_broken, @testset
       @test diagview(dename(a)) == ones(2)
     end
   end
+  @testset "oneelement" begin
+    i = Index(3)
+    a = oneelement(i => 2)
+    @test a isa ITensor
+    @test ndims(a) == 1
+    @test issetequal(inds(a), (i,))
+    @test eltype(a) === Bool
+    @test a[1] == 0
+    @test a[2] == 1
+    @test a[3] == 0
+
+    i = Index(3)
+    a = oneelement(Float32, i => 2)
+    @test a isa ITensor
+    @test ndims(a) == 1
+    @test issetequal(inds(a), (i,))
+    @test eltype(a) === Float32
+    @test a[1] == 0
+    @test a[2] == 1
+    @test a[3] == 0
+  end
 end