make Tree functions data-last

gcanti · May 31, 2019 · 533d561 · 533d561
1 parent badab02
commit 533d561
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Showing 3 changed files with 12 additions and 10 deletions.
diff --git a/docs/modules/Tree.ts.md b/docs/modules/Tree.ts.md
@@ -134,7 +134,7 @@ Added in v2.0.0
 **Signature**
 
 ```ts
-export function elem<A>(E: Eq<A>): (a: A, fa: Tree<A>) => boolean { ... }
+export function elem<A>(E: Eq<A>): (a: A) => (fa: Tree<A>) => boolean { ... }
 ```
 
 Added in v2.0.0

diff --git a/src/Tree.ts b/src/Tree.ts
@@ -208,14 +208,16 @@ export function unfoldForestM<M>(
 /**
  * @since 2.0.0
  */
-export function elem<A>(E: Eq<A>): (a: A, fa: Tree<A>) => boolean {
-  const go = (a: A, fa: Tree<A>): boolean => {
-    if (E.equals(a, fa.value)) {
-      return true
+export function elem<A>(E: Eq<A>): (a: A) => (fa: Tree<A>) => boolean {
+  return a => {
+    const go = (fa: Tree<A>): boolean => {
+      if (E.equals(a, fa.value)) {
+        return true
+      }
+      return fa.forest.some(tree => go(tree))
     }
-    return fa.forest.some(tree => go(a, tree))
+    return go
   }
-  return go
 }
 
 /**

diff --git a/test/Tree.ts b/test/Tree.ts
@@ -147,9 +147,9 @@ describe('Tree', () => {
     }
     const S: Eq<User> = contramap(eqNumber, (user: User) => user.id)
     const users = make({ id: 1 }, [make({ id: 1 }, [make({ id: 3 }), make({ id: 4 })]), make({ id: 2 })])
-    assert.strictEqual(elem(S)({ id: 1 }, users), true)
-    assert.strictEqual(elem(S)({ id: 4 }, users), true)
-    assert.strictEqual(elem(S)({ id: 5 }, users), false)
+    assert.strictEqual(elem(S)({ id: 1 })(users), true)
+    assert.strictEqual(elem(S)({ id: 4 })(users), true)
+    assert.strictEqual(elem(S)({ id: 5 })(users), false)
   })
 
   it('getShow', () => {