select adjacent basic cases #3

codingedgar · codingedgar · commit 98a05dfff458 · 2021-08-11T20:11:12.000-04:00
diff --git a/package.json b/package.json
@@ -16,12 +16,13 @@
   },
   "devDependencies": {
     "@types/jest": "^27.0.0",
+    "@types/ramda": "types/npm-ramda#dist",
     "fast-check": "^2.17.0",
     "jest": "^27.0.6",
     "ts-jest": "^27.0.4",
     "typescript": "^4.3.5"
   },
   "dependencies": {
-    "fp-ts": "^2.11.1"
+    "ramda": "^0.27.1"
   }
 }
diff --git a/src/index.ts b/src/index.ts
@@ -1,40 +1,106 @@
+import { head, take } from "ramda";
+
 export type Context = {
   list: string[],
   selected: string[],
+  adjacentPivot: undefined,
+  lastSelected: undefined,
+} | {
+  list: string[],
+  selected: string[],
+  adjacentPivot: string,
+  lastSelected: string,
 }
 
 type Command =
   | { type: "SELECT ONE", id: string }
   | { type: "TOGGLE SELECTION", id: string }
   | { type: "DESELECT ALL" }
+  | { type: "SELECT ADJACENT", id: string }
+
+function listIncludesAndIsNotEmpty(list: string[], item: string) {
+  return list.length > 0 && list.includes(item)
+}
 
 export function multiselect(context: Context, command: Command): Context {
-  if (command.type === "SELECT ONE" && context.list.includes(command.id)) {
+  if (
+    command.type === "SELECT ONE" &&
+    listIncludesAndIsNotEmpty(context.list, command.id)
+  ) {
+    return {
+      ...context,
+      selected: [command.id],
+      adjacentPivot: command.id,
+      lastSelected: command.id,
+    };
+  } else if (
+      command.type === 'TOGGLE SELECTION' &&
+      listIncludesAndIsNotEmpty(context.list, command.id) &&
+      context.selected.includes(command.id) &&
+      context.selected.length === 1
+  ) {
+    const index = context.selected.indexOf(command.id)
     return {
       ...context,
-      selected: [command.id]
+      selected: [],
+      adjacentPivot: undefined,
+      lastSelected: undefined
     };
   } else if (
       command.type === 'TOGGLE SELECTION' &&
-      context.list.includes(command.id) &&
+      listIncludesAndIsNotEmpty(context.list, command.id) &&
       context.selected.includes(command.id)
-    ) {
+  ) {
+    const index = context.selected.indexOf(command.id);
+    const adjacentPivot= (index < (context.selected.length - 1))
+        ? context.selected[index + 1]
+        : context.selected[index - 1];
     return {
       ...context,
       selected: context.selected.filter(x => x !== command.id),
+      adjacentPivot,
+      lastSelected: adjacentPivot
     };
   } else if (
-      command.type === 'TOGGLE SELECTION' &&
-      context.list.includes(command.id)
-    ) {
+    command.type === 'TOGGLE SELECTION' &&
+    context.list.includes(command.id)
+  ) {
     return {
       ...context,
-      selected: context.selected.concat([command.id])
+      selected: context.selected.concat([command.id]),
+      adjacentPivot: command.id,
+      lastSelected: command.id
     };
   } else if (command.type === "DESELECT ALL") {
     return {
       ...context,
-      selected: []
+      selected: [],
+      adjacentPivot: undefined,
+      lastSelected: undefined
+    }
+  } else if (
+    command.type === "SELECT ADJACENT" &&
+    listIncludesAndIsNotEmpty(context.list, command.id) &&
+    context.selected.length === 0
+  ) {
+    const n = context.list.indexOf(command.id) + 1;
+    return {
+      ...context,
+      selected: take(n, context.list),
+      adjacentPivot: head(context.list)!,
+      lastSelected: command.id,
+    }
+  } else if (
+    command.type === "SELECT ADJACENT" &&
+    listIncludesAndIsNotEmpty(context.list, command.id) &&
+    context.adjacentPivot
+  ) {
+    const start = context.list.indexOf(context.adjacentPivot);
+    const n = context.list.indexOf(command.id);
+    return {
+      ...context,
+      selected: context.list.slice(Math.min(start, n), Math.max(start, n) + 1),
+      lastSelected: command.id
     }
   } else {
     return context;
diff --git a/src/spec/deselectAll.spec.ts b/src/spec/deselectAll.spec.ts
@@ -23,20 +23,32 @@ describe('Deselect All', () => {
           list,
           selected
         }) => {
+          const context = (selected.length)
+            ? {
+              list,
+              selected,
+              adjacentPivot: selected[selected.length - 1],
+              lastSelected: selected[selected.length - 1], 
+            }
+            : {
+              list,
+              selected,
+              adjacentPivot: undefined,
+              lastSelected: undefined,
+            }
           expect(
             multiselect(
-              {
-                list,
-                selected,
-              },
+              context,
               {
                 type: "DESELECT ALL",
               }
             )
           )
           .toEqual({
             list,
-            selected: []
+            selected: [],
+            adjacentPivot: undefined,
+            lastSelected: undefined
           })
         }
       )
diff --git a/src/spec/selectAdjacent.spec.ts b/src/spec/selectAdjacent.spec.ts
@@ -0,0 +1,121 @@
+import fc from 'fast-check';
+import { take, last, head, startsWith } from "ramda";
+import { multiselect } from '../index';
+
+describe('Select Adjacent', () => {
+  test('should select from top to bottom in an empty list', () => {
+
+    fc.assert(
+      fc.property(
+        fc.set(
+          fc.string(),
+          { minLength: 1 }
+        )
+        .chain(list =>
+          fc.record({
+            list: fc.constant(list),
+            selection: fc.integer(1, list.length)
+              .map(n => take(n, list))
+          })
+        ),
+        ({
+          list,
+          selection,
+        }) => {
+          const id = last(selection)!;
+          expect(
+            multiselect({
+                list,
+                selected: [],
+                adjacentPivot: undefined,
+                lastSelected: undefined
+              },
+              {
+                type: "SELECT ADJACENT",
+                id,
+              }
+            )
+          )
+          .toEqual({
+            list,
+            selected: selection,
+            adjacentPivot: head(selection)!,
+            lastSelected: id
+          })
+        }
+      )
+    )
+  });
+  
+  test('should select from the last adjacent pivot', () => {
+
+    fc.assert(
+      fc.property(
+        fc.set(
+          fc.string(),
+          { minLength: 1 }
+        )
+        .chain(list =>
+          fc.record({
+            list: fc.constant(list),
+            selection: fc
+              .integer(0, list.length - 1)
+              .chain(start =>
+                fc
+                  .integer(start + 1, list.length)
+                  .map(end =>
+                    list.slice(start, end)
+                  )
+              ),
+            direction: fc.boolean(),
+          })
+        )
+        .map(
+          ({
+            list,
+            selection,
+            direction
+          }) => ({
+            list,
+            selection,
+            start: direction ? head(selection)! : last(selection)!,
+            end: direction ? last(selection)! : head(selection)!
+          })
+        ),
+        ({
+          list,
+          selection,
+          start,
+          end
+        }) => {
+          expect(
+            multiselect(
+              multiselect({
+                list,
+                selected: [],
+                adjacentPivot: undefined,
+                lastSelected: undefined
+              },
+              {
+                type: "SELECT ONE",
+                id: start,
+              }
+            ),
+            {
+              type: "SELECT ADJACENT",
+              id: end
+            }
+            )
+          )
+          .toEqual({
+            list,
+            selected: selection,
+            adjacentPivot: start,
+            lastSelected: end
+          })
+        }
+      )
+    );
+
+  });
+})
diff --git a/src/spec/selectOne.spec.ts b/src/spec/selectOne.spec.ts
@@ -25,6 +25,8 @@ describe('Select One Item', () => {
               multiselect({
                   list,
                   selected: [],
+                  adjacentPivot: undefined,
+                  lastSelected: undefined,
                 },
                 {
                   type: "SELECT ONE",
@@ -34,7 +36,9 @@ describe('Select One Item', () => {
             )
               .toEqual({
                 list,
-                selected: [id]
+                selected: [id],
+                adjacentPivot: id,
+                lastSelected: id,
               })
           }
         )
@@ -68,6 +72,8 @@ describe('Select One Item', () => {
               multiselect({
                   list,
                   selected: [selectedId],
+                  adjacentPivot: selectedId,
+                  lastSelected: selectedId,
                 },
                 {
                   type: "SELECT ONE",
@@ -77,7 +83,9 @@ describe('Select One Item', () => {
             )
               .toEqual({
                 list,
-                selected: [id]
+                selected: [id],
+                adjacentPivot: id,
+                lastSelected: id
               })
           }
         )
diff --git a/src/spec/toggleSelection.spec.ts b/src/spec/toggleSelection.spec.ts
diff --git a/yarn.lock b/yarn.lock

Original file line number	Diff line number	Diff line change
`@@ -25,6 +25,8 @@ describe('Select One Item', () => {`
`25`	`25`	`multiselect({`
`26`	`26`	`list,`
`27`	`27`	`selected: [],`
	`28`	`+ adjacentPivot: undefined,`
	`29`	`+ lastSelected: undefined,`
`28`	`30`	`},`
`29`	`31`	`{`
`30`	`32`	`type: "SELECT ONE",`
`@@ -34,7 +36,9 @@ describe('Select One Item', () => {`
`34`	`36`	`)`
`35`	`37`	`.toEqual({`
`36`	`38`	`list,`
`37`		`- selected: [id]`
	`39`	`+ selected: [id],`
	`40`	`+ adjacentPivot: id,`
	`41`	`+ lastSelected: id,`
`38`	`42`	`})`
`39`	`43`	`}`
`40`	`44`	`)`
`@@ -68,6 +72,8 @@ describe('Select One Item', () => {`
`68`	`72`	`multiselect({`
`69`	`73`	`list,`
`70`	`74`	`selected: [selectedId],`
	`75`	`+ adjacentPivot: selectedId,`
	`76`	`+ lastSelected: selectedId,`
`71`	`77`	`},`
`72`	`78`	`{`
`73`	`79`	`type: "SELECT ONE",`
`@@ -77,7 +83,9 @@ describe('Select One Item', () => {`
`77`	`83`	`)`
`78`	`84`	`.toEqual({`
`79`	`85`	`list,`
`80`		`- selected: [id]`
	`86`	`+ selected: [id],`
	`87`	`+ adjacentPivot: id,`
	`88`	`+ lastSelected: id`
`81`	`89`	`})`
`82`	`90`	`}`
`83`	`91`	`)`