HTML のドラッグ&ドロップ (3. SAFE Stack の ToDo アプリに実装)
HTML のドラッグ & ドロップ API を使って、SAFE Stack の ToDo アプリで項目の並べ替えをできるようにした。 変更したファイルは src/Client/Index.fs 、 src/Server/Server.fs 、 src/Shared/Shared.fs の 3 つだった。
F# で書いたコードから Fable を使って HTML の API を呼び出せることを確認できた。 JavaScript でお馴染の on… (…のところはイベント名) のようなイベントハンドラに F# の関数が渡せるのは分っていたけど、自分の書いたコードで実際に動いてくれると更に感動する。 また、アクティブパターンの利用例によくある正規表現のパターンマッチも使えて、思っていた以上に F# そのものがクライアントのコードで動いてくれた。 Fable 、とても有り難い。
ソースコードをこのページに載せる。差分は SAFE Stack のプロジェクトを作成したときのデフォルトのサンプルとの比較になっている。
一覧
- 差分
- 全文
差分
src/Client/Index.fs の差分
diff --git a/src/Client/Index.fs b/src/Client/Index.fs
--- a/src/Client/Index.fs
+++ b/src/Client/Index.fs
@@ -2,15 +2,34 @@ module Index
open Elmish
open Fable.Remoting.Client
+open Browser.Types
open Shared
+open System.Text.RegularExpressions
+let (|RE|_|) re str =
+ let m = Regex.Match(str, re)
+ if m.Success
+ then Some (List.tail [ for x in m.Groups -> x.Value ])
+ else None
-type Model = { Todos: Todo list; Input: string }
type Msg =
| GotTodos of Todo list
| SetInput of string
| AddTodo
| AddedTodo of Todo
+ | MoveTodo of string * string
+ | MovedTodo of Todo List
+ | DragStart of string
+ | DragOver of string
+ | DragEnter of string
+ | DragLeave of string
+
+type Model = {
+ Todos: Todo list;
+ Input: string;
+ DragFrom: string option;
+ DragOn: string option;
+}
let todosApi =
Remoting.createApi ()
@@ -18,13 +37,49 @@ let todosApi =
|> Remoting.buildProxy<ITodosApi>
let init () : Model * Cmd<Msg> =
- let model = { Todos = []; Input = "" }
+ let model = {
+ Todos = [];
+ Input = "";
+ DragFrom = None;
+ DragOn = None;
+ }
let cmd =
Cmd.OfAsync.perform todosApi.getTodos () GotTodos
model, cmd
+let todo_idx2label (idx: int) =
+ "todo:" + (string idx)
+
+let todo_label2idxOpt (label: string) =
+ let elems = label.Split [|':'|]
+ if Array.length elems = 2 then
+ let idxStr = Array.get elems 1
+ match idxStr with
+ | RE @"^\d+$" [] -> Some (int idxStr)
+ | _ -> None
+ else
+ None
+
+let dropTarget_pos2label (pos: MoveDstPosition) =
+ let posStr =
+ match pos with
+ | InFrontOf idx -> string idx
+ | Last -> "last"
+ "dropTarget:" + posStr
+
+let dropTarget_label2posOpt (label: string) =
+ let elems = label.Split [|':'|]
+ if Array.length elems = 2 then
+ let posStr = Array.get elems 1
+ match posStr with
+ | "last" -> Some Last
+ | RE @"^\d+$" [] -> Some (InFrontOf (int posStr))
+ | _ -> None
+ else
+ None
+
let update (msg: Msg) (model: Model) : Model * Cmd<Msg> =
match msg with
| GotTodos todos -> { model with Todos = todos }, Cmd.none
@@ -40,6 +95,46 @@ let update (msg: Msg) (model: Model) : Model * Cmd<Msg> =
{ model with
Todos = model.Todos @ [ todo ] },
Cmd.none
+ | MoveTodo (srcLabel, dstLabel) ->
+ // ToDo: implement: more gentle error handling
+ let cmd =
+ if Some srcLabel <> model.DragFrom then
+ // error: mismatched source labels
+ Cmd.none
+ else
+ let srcIdxOpt = todo_label2idxOpt srcLabel
+ let dstPosOpt = dropTarget_label2posOpt dstLabel
+ match (srcIdxOpt, dstPosOpt) with
+ | (None, _) -> Cmd.none // error: bad source lable
+ | (_, None) -> Cmd.none // error: bad destination label
+ | (Some s, Some d) -> Cmd.OfAsync.perform todosApi.moveTodo (s, d) MovedTodo
+ { model with
+ DragFrom = None;
+ DragOn = None;
+ },
+ cmd
+ | MovedTodo todos ->
+ { model with
+ Todos = todos; },
+ Cmd.none
+ | DragStart label ->
+ { model with
+ DragFrom = Some label;
+ },
+ Cmd.none
+ | DragOver label ->
+ model,
+ Cmd.none
+ | DragEnter label ->
+ { model with
+ DragOn = Some label;
+ },
+ Cmd.none
+ | DragLeave label ->
+ { model with
+ DragOn = None;
+ },
+ Cmd.none
open Feliz
open Feliz.Bulma
@@ -58,12 +153,74 @@ let navBrand =
]
]
+let evtHdlr_dragStart (dispatch: Msg -> unit) (label: string) (evt: DragEvent) =
+ evt.dataTransfer.setData ("text/plain", label) |> ignore
+ evt.dataTransfer.effectAllowed <- "move"
+ DragStart label |> dispatch
+
+let evtHdlr_dragOver (dispatch: Msg -> unit) (label: string) (evt: DragEvent) =
+ evt.preventDefault ()
+ evt.dataTransfer.dropEffect <- "move"
+ DragOver label |> dispatch
+
+let evtHdlr_dragEnter (dispatch: Msg -> unit) (label: string) (evt: DragEvent) =
+ evt.preventDefault ()
+ evt.dataTransfer.dropEffect <- "move"
+ DragEnter label |> dispatch
+
+let evtHdlr_dragLeave (dispatch: Msg -> unit) (label: string) (evt: DragEvent) =
+ DragLeave label |> dispatch
+
+let evtHdlr_drop (dispatch: Msg -> unit) (label: string) (evt: DragEvent) =
+ let srcLabel = evt.dataTransfer.getData ("text/plain")
+ evt.preventDefault ()
+ MoveTodo (srcLabel, label) |> dispatch
+
+let htmlLi_todoItem (model: Model) (dispatch: Msg -> unit) (todo: Todo) (idx: int) =
+ let label = todo_idx2label idx
+ let text = (idx + 1 |> string) + ". " + todo.Description
+ Html.li [
+ prop.id label
+ prop.draggable true
+ prop.onDragStart <| evtHdlr_dragStart dispatch label
+ prop.style [
+ style.listStyleType.none
+ style.margin 0
+ ]
+ prop.text text
+ ]
+
+let htmlLi_dropTarget (model: Model) (dispatch: Msg -> unit) (pos: MoveDstPosition) =
+ let label = dropTarget_pos2label pos
+ let style =
+ let basic_style = [
+ style.listStyleType.none
+ style.margin 0
+ style.padding (length.em 0.5)
+ ]
+ if model.DragOn = Some label then
+ style.backgroundColor.pink :: basic_style
+ else
+ basic_style
+ Html.li [
+ prop.id label
+ prop.onDragOver <| evtHdlr_dragOver dispatch label
+ prop.onDragEnter <| evtHdlr_dragEnter dispatch label
+ prop.onDragLeave <| evtHdlr_dragLeave dispatch label
+ prop.onDrop <| evtHdlr_drop dispatch label
+ prop.style style
+ prop.text ""
+ ]
+
let containerBox (model: Model) (dispatch: Msg -> unit) =
+ let todoIdxs = seq { 0 .. model.Todos.Length - 1 } |> List.ofSeq
Bulma.box [
Bulma.content [
Html.ol [
- for todo in model.Todos do
- Html.li [ prop.text todo.Description ]
+ for todo, idx in List.zip model.Todos todoIdxs do
+ htmlLi_dropTarget model dispatch (InFrontOf idx)
+ htmlLi_todoItem model dispatch todo idx
+ htmlLi_dropTarget model dispatch Last
]
]
Bulma.field.div [
@@ -76,6 +233,7 @@ let containerBox (model: Model) (dispatch: Msg -> unit) =
prop.value model.Input
prop.placeholder "What needs to be done?"
prop.onChange (fun x -> SetInput x |> dispatch)
+ prop.onKeyUp (key.enter, fun _ -> dispatch AddTodo)
]
]
]src/Server/Server.fs の差分
diff --git a/src/Server/Server.fs b/src/Server/Server.fs
--- a/src/Server/Server.fs
+++ b/src/Server/Server.fs
@@ -7,6 +7,7 @@ open Saturn
open Shared
type Storage() =
+ // ResizeArray is System.Collections.Generic.List
let todos = ResizeArray<_>()
member __.GetTodos() = List.ofSeq todos
@@ -18,6 +19,19 @@ type Storage() =
else
Error "Invalid todo"
+ // // List version
+ // member __.MoveTodo (srcIdx: int) (dstPos: MoveDstPosition) =
+ // let todosList = List.ofSeq todos
+ // let newTodoList = TodoList.move todosList srcIdx dstPos
+ // todos.Clear()
+ // todos.AddRange(newTodoList)
+ // Ok newTodoList
+
+ // ResizeArray version
+ member __.MoveTodo (srcIdx: int) (dstPos: MoveDstPosition) =
+ TodoResizeArray.move todos srcIdx dstPos
+ Ok (List.ofSeq todos)
+
let storage = Storage()
storage.AddTodo(Todo.create "Create new SAFE project")
@@ -37,6 +51,13 @@ let todosApi =
match storage.AddTodo todo with
| Ok () -> return todo
| Error e -> return failwith e
+ }
+ moveTodo =
+ fun (srcIdx, dstPos) ->
+ async {
+ match storage.MoveTodo srcIdx dstPos with
+ | Ok newTodoList -> return newTodoList
+ | Error e -> return failwith e
} }
let webApp =src/Shared/Shared.fs の差分
diff --git a/src/Shared/Shared.fs b/src/Shared/Shared.fs
--- a/src/Shared/Shared.fs
+++ b/src/Shared/Shared.fs
@@ -4,6 +4,10 @@ open System
type Todo = { Id: Guid; Description: string }
+type MoveDstPosition =
+ | InFrontOf of int
+ | Last
+
module Todo =
let isValid (description: string) =
String.IsNullOrWhiteSpace description |> not
@@ -12,10 +16,68 @@ module Todo =
{ Id = Guid.NewGuid()
Description = description }
+module TodoList =
+ let move (todos: Todo list) (srcIdx: int) (dstPos: MoveDstPosition) =
+ let length = List.length todos
+ let lastIdx = length - 1
+ let todoSrc = List.item srcIdx todos
+ let todosSub1 = todos.[0 .. (srcIdx - 1)]
+ let todosSub2 = todos.[(srcIdx + 1) .. lastIdx]
+ match dstPos with
+ | Last -> todosSub1 @ todosSub2 @ [todoSrc]
+ | InFrontOf dstIdx ->
+ if dstIdx = srcIdx then
+ todos
+ else if dstIdx < srcIdx then
+ let splitIdx = dstIdx
+ let (todosSub1a, todosSub1b) = List.splitAt splitIdx todosSub1
+ todosSub1a @ [todoSrc] @ todosSub1b @ todosSub2
+ else // dstIdx > srcIdx
+ let splitIdx = dstIdx - (srcIdx + 1)
+ let (todosSub2a, todosSub2b) = List.splitAt splitIdx todosSub2
+ todosSub1 @ todosSub2a @ [todoSrc] @ todosSub2b
+
+module TodoResizeArray =
+ let move (todos: ResizeArray<Todo>) (srcIdx: int) (dstPos: MoveDstPosition) =
+ let todoSrc = todos.[srcIdx]
+ let todosSub1 = todos.GetRange(0, srcIdx)
+ let todosSub2 = todos.GetRange(srcIdx + 1, todos.Count - (srcIdx + 1))
+ match dstPos with
+ | Last ->
+ todos.Clear ()
+ todos.AddRange todosSub1
+ todos.AddRange todosSub2
+ todos.AddRange [todoSrc]
+ ()
+ | InFrontOf dstIdx ->
+ if dstIdx = srcIdx then
+ ()
+ else if dstIdx < srcIdx then
+ let splitIdx = dstIdx
+ let todosSub1a = todosSub1.GetRange(0, splitIdx)
+ let todosSub1b = todosSub1.GetRange(splitIdx, todosSub1.Count - splitIdx)
+ todos.Clear ()
+ todos.AddRange todosSub1a
+ todos.AddRange [todoSrc]
+ todos.AddRange todosSub1b
+ todos.AddRange todosSub2
+ ()
+ else // dstIdx > srcIdx
+ let splitIdx = dstIdx - (srcIdx + 1)
+ let todosSub2a = todosSub2.GetRange(0, splitIdx)
+ let todosSub2b = todosSub2.GetRange(splitIdx, todosSub2.Count - splitIdx)
+ todos.Clear ()
+ todos.AddRange todosSub1
+ todos.AddRange todosSub2a
+ todos.AddRange [todoSrc]
+ todos.AddRange todosSub2b
+ ()
+
module Route =
let builder typeName methodName =
sprintf "/api/%s/%s" typeName methodName
type ITodosApi =
{ getTodos: unit -> Async<Todo list>
- addTodo: Todo -> Async<Todo> }
+ addTodo: Todo -> Async<Todo>
+ moveTodo: int * MoveDstPosition -> Async<Todo List> }全文
src/Client/Index.fs の全文
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
module Index
open Elmish
open Fable.Remoting.Client
open Browser.Types
open Shared
open System.Text.RegularExpressions
let (|RE|_|) re str =
let m = Regex.Match(str, re)
if m.Success
then Some (List.tail [ for x in m.Groups -> x.Value ])
else None
type Msg =
| GotTodos of Todo list
| SetInput of string
| AddTodo
| AddedTodo of Todo
| MoveTodo of string * string
| MovedTodo of Todo List
| DragStart of string
| DragOver of string
| DragEnter of string
| DragLeave of string
type Model = {
Todos: Todo list;
Input: string;
DragFrom: string option;
DragOn: string option;
}
let todosApi =
Remoting.createApi ()
|> Remoting.withRouteBuilder Route.builder
|> Remoting.buildProxy<ITodosApi>
let init () : Model * Cmd<Msg> =
let model = {
Todos = [];
Input = "";
DragFrom = None;
DragOn = None;
}
let cmd =
Cmd.OfAsync.perform todosApi.getTodos () GotTodos
model, cmd
let todo_idx2label (idx: int) =
"todo:" + (string idx)
let todo_label2idxOpt (label: string) =
let elems = label.Split [|':'|]
if Array.length elems = 2 then
let idxStr = Array.get elems 1
match idxStr with
| RE @"^\d+$" [] -> Some (int idxStr)
| _ -> None
else
None
let dropTarget_pos2label (pos: MoveDstPosition) =
let posStr =
match pos with
| InFrontOf idx -> string idx
| Last -> "last"
"dropTarget:" + posStr
let dropTarget_label2posOpt (label: string) =
let elems = label.Split [|':'|]
if Array.length elems = 2 then
let posStr = Array.get elems 1
match posStr with
| "last" -> Some Last
| RE @"^\d+$" [] -> Some (InFrontOf (int posStr))
| _ -> None
else
None
let update (msg: Msg) (model: Model) : Model * Cmd<Msg> =
match msg with
| GotTodos todos -> { model with Todos = todos }, Cmd.none
| SetInput value -> { model with Input = value }, Cmd.none
| AddTodo ->
let todo = Todo.create model.Input
let cmd =
Cmd.OfAsync.perform todosApi.addTodo todo AddedTodo
{ model with Input = "" }, cmd
| AddedTodo todo ->
{ model with
Todos = model.Todos @ [ todo ] },
Cmd.none
| MoveTodo (srcLabel, dstLabel) ->
// ToDo: implement: more gentle error handling
let cmd =
if Some srcLabel <> model.DragFrom then
// error: mismatched source labels
Cmd.none
else
let srcIdxOpt = todo_label2idxOpt srcLabel
let dstPosOpt = dropTarget_label2posOpt dstLabel
match (srcIdxOpt, dstPosOpt) with
| (None, _) -> Cmd.none // error: bad source lable
| (_, None) -> Cmd.none // error: bad destination label
| (Some s, Some d) -> Cmd.OfAsync.perform todosApi.moveTodo (s, d) MovedTodo
{ model with
DragFrom = None;
DragOn = None;
},
cmd
| MovedTodo todos ->
{ model with
Todos = todos; },
Cmd.none
| DragStart label ->
{ model with
DragFrom = Some label;
},
Cmd.none
| DragOver label ->
model,
Cmd.none
| DragEnter label ->
{ model with
DragOn = Some label;
},
Cmd.none
| DragLeave label ->
{ model with
DragOn = None;
},
Cmd.none
open Feliz
open Feliz.Bulma
let navBrand =
Bulma.navbarBrand.div [
Bulma.navbarItem.a [
prop.href "https://safe-stack.github.io/"
navbarItem.isActive
prop.children [
Html.img [
prop.src "/favicon.png"
prop.alt "Logo"
]
]
]
]
let evtHdlr_dragStart (dispatch: Msg -> unit) (label: string) (evt: DragEvent) =
evt.dataTransfer.setData ("text/plain", label) |> ignore
evt.dataTransfer.effectAllowed <- "move"
DragStart label |> dispatch
let evtHdlr_dragOver (dispatch: Msg -> unit) (label: string) (evt: DragEvent) =
evt.preventDefault ()
evt.dataTransfer.dropEffect <- "move"
DragOver label |> dispatch
let evtHdlr_dragEnter (dispatch: Msg -> unit) (label: string) (evt: DragEvent) =
evt.preventDefault ()
evt.dataTransfer.dropEffect <- "move"
DragEnter label |> dispatch
let evtHdlr_dragLeave (dispatch: Msg -> unit) (label: string) (evt: DragEvent) =
DragLeave label |> dispatch
let evtHdlr_drop (dispatch: Msg -> unit) (label: string) (evt: DragEvent) =
let srcLabel = evt.dataTransfer.getData ("text/plain")
evt.preventDefault ()
MoveTodo (srcLabel, label) |> dispatch
let htmlLi_todoItem (model: Model) (dispatch: Msg -> unit) (todo: Todo) (idx: int) =
let label = todo_idx2label idx
let text = (idx + 1 |> string) + ". " + todo.Description
Html.li [
prop.id label
prop.draggable true
prop.onDragStart <| evtHdlr_dragStart dispatch label
prop.style [
style.listStyleType.none
style.margin 0
]
prop.text text
]
let htmlLi_dropTarget (model: Model) (dispatch: Msg -> unit) (pos: MoveDstPosition) =
let label = dropTarget_pos2label pos
let style =
let basic_style = [
style.listStyleType.none
style.margin 0
style.padding (length.em 0.5)
]
if model.DragOn = Some label then
style.backgroundColor.pink :: basic_style
else
basic_style
Html.li [
prop.id label
prop.onDragOver <| evtHdlr_dragOver dispatch label
prop.onDragEnter <| evtHdlr_dragEnter dispatch label
prop.onDragLeave <| evtHdlr_dragLeave dispatch label
prop.onDrop <| evtHdlr_drop dispatch label
prop.style style
prop.text ""
]
let containerBox (model: Model) (dispatch: Msg -> unit) =
let todoIdxs = seq { 0 .. model.Todos.Length - 1 } |> List.ofSeq
Bulma.box [
Bulma.content [
Html.ol [
for todo, idx in List.zip model.Todos todoIdxs do
htmlLi_dropTarget model dispatch (InFrontOf idx)
htmlLi_todoItem model dispatch todo idx
htmlLi_dropTarget model dispatch Last
]
]
Bulma.field.div [
field.isGrouped
prop.children [
Bulma.control.p [
control.isExpanded
prop.children [
Bulma.input.text [
prop.value model.Input
prop.placeholder "What needs to be done?"
prop.onChange (fun x -> SetInput x |> dispatch)
prop.onKeyUp (key.enter, fun _ -> dispatch AddTodo)
]
]
]
Bulma.control.p [
Bulma.button.a [
color.isPrimary
prop.disabled (Todo.isValid model.Input |> not)
prop.onClick (fun _ -> dispatch AddTodo)
prop.text "Add"
]
]
]
]
]
let view (model: Model) (dispatch: Msg -> unit) =
Bulma.hero [
hero.isFullHeight
color.isPrimary
prop.style [
style.backgroundSize "cover"
style.backgroundImageUrl "https://unsplash.it/1200/900?random"
style.backgroundPosition "no-repeat center center fixed"
]
prop.children [
Bulma.heroHead [
Bulma.navbar [
Bulma.container [ navBrand ]
]
]
Bulma.heroBody [
Bulma.container [
Bulma.column [
column.is6
column.isOffset3
prop.children [
Bulma.title [
text.hasTextCentered
prop.text "todo app"
]
containerBox model dispatch
]
]
]
]
]
]
src/Server/Server.fs の全文
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
module Server
open Fable.Remoting.Server
open Fable.Remoting.Giraffe
open Saturn
open Shared
type Storage() =
// ResizeArray is System.Collections.Generic.List
let todos = ResizeArray<_>()
member __.GetTodos() = List.ofSeq todos
member __.AddTodo(todo: Todo) =
if Todo.isValid todo.Description then
todos.Add todo
Ok()
else
Error "Invalid todo"
// // List version
// member __.MoveTodo (srcIdx: int) (dstPos: MoveDstPosition) =
// let todosList = List.ofSeq todos
// let newTodoList = TodoList.move todosList srcIdx dstPos
// todos.Clear()
// todos.AddRange(newTodoList)
// Ok newTodoList
// ResizeArray version
member __.MoveTodo (srcIdx: int) (dstPos: MoveDstPosition) =
TodoResizeArray.move todos srcIdx dstPos
Ok (List.ofSeq todos)
let storage = Storage()
storage.AddTodo(Todo.create "Create new SAFE project")
|> ignore
storage.AddTodo(Todo.create "Write your app")
|> ignore
storage.AddTodo(Todo.create "Ship it !!!")
|> ignore
let todosApi =
{ getTodos = fun () -> async { return storage.GetTodos() }
addTodo =
fun todo ->
async {
match storage.AddTodo todo with
| Ok () -> return todo
| Error e -> return failwith e
}
moveTodo =
fun (srcIdx, dstPos) ->
async {
match storage.MoveTodo srcIdx dstPos with
| Ok newTodoList -> return newTodoList
| Error e -> return failwith e
} }
let webApp =
Remoting.createApi ()
|> Remoting.withRouteBuilder Route.builder
|> Remoting.fromValue todosApi
|> Remoting.buildHttpHandler
let app =
application {
url "http://0.0.0.0:8085"
use_router webApp
memory_cache
use_static "public"
use_gzip
}
run app
src/Shared/Shared.fs の全文
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
namespace Shared
open System
type Todo = { Id: Guid; Description: string }
type MoveDstPosition =
| InFrontOf of int
| Last
module Todo =
let isValid (description: string) =
String.IsNullOrWhiteSpace description |> not
let create (description: string) =
{ Id = Guid.NewGuid()
Description = description }
module TodoList =
let move (todos: Todo list) (srcIdx: int) (dstPos: MoveDstPosition) =
let length = List.length todos
let lastIdx = length - 1
let todoSrc = List.item srcIdx todos
let todosSub1 = todos.[0 .. (srcIdx - 1)]
let todosSub2 = todos.[(srcIdx + 1) .. lastIdx]
match dstPos with
| Last -> todosSub1 @ todosSub2 @ [todoSrc]
| InFrontOf dstIdx ->
if dstIdx = srcIdx then
todos
else if dstIdx < srcIdx then
let splitIdx = dstIdx
let (todosSub1a, todosSub1b) = List.splitAt splitIdx todosSub1
todosSub1a @ [todoSrc] @ todosSub1b @ todosSub2
else // dstIdx > srcIdx
let splitIdx = dstIdx - (srcIdx + 1)
let (todosSub2a, todosSub2b) = List.splitAt splitIdx todosSub2
todosSub1 @ todosSub2a @ [todoSrc] @ todosSub2b
module TodoResizeArray =
let move (todos: ResizeArray<Todo>) (srcIdx: int) (dstPos: MoveDstPosition) =
let todoSrc = todos.[srcIdx]
let todosSub1 = todos.GetRange(0, srcIdx)
let todosSub2 = todos.GetRange(srcIdx + 1, todos.Count - (srcIdx + 1))
match dstPos with
| Last ->
todos.Clear ()
todos.AddRange todosSub1
todos.AddRange todosSub2
todos.AddRange [todoSrc]
()
| InFrontOf dstIdx ->
if dstIdx = srcIdx then
()
else if dstIdx < srcIdx then
let splitIdx = dstIdx
let todosSub1a = todosSub1.GetRange(0, splitIdx)
let todosSub1b = todosSub1.GetRange(splitIdx, todosSub1.Count - splitIdx)
todos.Clear ()
todos.AddRange todosSub1a
todos.AddRange [todoSrc]
todos.AddRange todosSub1b
todos.AddRange todosSub2
()
else // dstIdx > srcIdx
let splitIdx = dstIdx - (srcIdx + 1)
let todosSub2a = todosSub2.GetRange(0, splitIdx)
let todosSub2b = todosSub2.GetRange(splitIdx, todosSub2.Count - splitIdx)
todos.Clear ()
todos.AddRange todosSub1
todos.AddRange todosSub2a
todos.AddRange [todoSrc]
todos.AddRange todosSub2b
()
module Route =
let builder typeName methodName =
sprintf "/api/%s/%s" typeName methodName
type ITodosApi =
{ getTodos: unit -> Async<Todo list>
addTodo: Todo -> Async<Todo>
moveTodo: int * MoveDstPosition -> Async<Todo List> }