Add tap, tapOk, tapError, tapSome

src/js/repromise.re

@@ -155,6 +155,11 @@ module Rejectable = {
   let on = (callback, promise) =>
     promise |> map(callback) |> ignore;
 
+  let tap = (callback, promise) => {
+    on(callback, promise);
+    promise;
+  };
+
   [@bs.scope "Promise"]
   [@bs.val]
   external rejected: 'e => rejectable(_, 'e) = "reject";
@@ -233,6 +238,7 @@ let resolved = Rejectable.resolved;
 let flatMap = Rejectable.flatMap;
 let map = Rejectable.map;
 let on = Rejectable.on;
+let tap = Rejectable.tap;
 let all = Rejectable.all;
 let all2 = Rejectable.all2;
 let all3 = Rejectable.all3;
@@ -289,6 +295,16 @@ let onError = (_callback, promise) =>
     | Error(_) => [%raw "_callback(result[0])"]
     });
 
+let tapOk = (callback, promise) => {
+  onOk(callback, promise);
+  promise;
+};
+
+let tapError = (callback, promise) => {
+  onError(callback, promise);
+  promise;
+};
+
 module Operators = {
   let (>|=) = (promise, callback) =>
     mapOk(callback, promise);
@@ -319,3 +335,8 @@ let onSome = (_callback, promise) =>
     | Some(_) => [%raw "_callback(Caml_option.valFromOption(option))"]
     | None => ()
     });
+
+let tapSome = (callback, promise) => {
+  onSome(callback, promise);
+  promise;
+};

src/js/repromise.rei

@@ -23,6 +23,8 @@ let map: ('a => 'b, promise('a)) => promise('b);
 
 let on: ('a => unit, promise('a)) => unit;
 
+let tap: ('a => unit, promise('a)) => promise('a);
+
 let flatMap: ('a => promise('b), promise('a)) => promise('b);
 
 let all: list(promise('a)) => promise(list('a));
@@ -71,6 +73,12 @@ let onOk:
 let onError:
   ('e => unit, promise(result(_, 'e))) => unit;
 
+let tapOk:
+  ('a => unit, promise(result('a, 'e))) => promise(result('a, 'e));
+
+let tapError:
+  ('e => unit, promise(result('a, 'e))) => promise(result('a, 'e));
+
 let flatMapOk:
   ('a => promise(result('b, 'e)), promise(result('a, 'e))) =>
     promise(result('b, 'e));
@@ -97,6 +105,9 @@ let mapSome:
 let onSome:
   ('a => unit, promise(option('a))) => unit;
 
+let tapSome:
+  ('a => unit, promise(option('a))) => promise(option('a));
+
 let flatMapSome:
   ('a => promise(option('b)), promise(option('a))) => promise(option('b));
 
@@ -118,6 +129,8 @@ module Rejectable: {
 
   let on: ('a => unit, rejectable('a, _)) => unit;
 
+  let tap: ('a => unit, rejectable('a, 'e)) => rejectable('a, 'e);
+
   let flatMap:
     ('a => rejectable('b, 'e), rejectable('a, 'e)) => rejectable('b, 'e);
 

src/native/repromise.re

@@ -214,6 +214,11 @@ let map = (mapper, promise) =>
 let on = (callback, promise) =>
   map(callback, promise) |> ignore;
 
+let tap = (callback, promise) => {
+  on(callback, promise);
+  promise;
+};
+
 let catch = (callback, promise) => {
   let outerPromise = newInternal();
 
@@ -494,6 +499,16 @@ let onError = (callback, promise) =>
     | Ok(_) => ()
     | Error(error) => callback(error));
 
+let tapOk = (callback, promise) => {
+  onOk(callback, promise);
+  promise;
+};
+
+let tapError = (callback, promise) => {
+  onError(callback, promise);
+  promise;
+};
+
 module Operators = {
   let (>|=) = (promise, callback) =>
     mapOk(callback, promise);
@@ -519,6 +534,11 @@ let onSome = (callback, promise) =>
     | Some(value) => callback(value)
     | None => ());
 
+let tapSome = (callback, promise) => {
+  onSome(callback, promise);
+  promise;
+};
+
 
 
 module Rejectable = {
@@ -538,6 +558,7 @@ module Rejectable = {
   let flatMap = flatMap;
   let map = map;
   let on = on;
+  let tap = tap;
   let catch = catch;
   let all = all;
   let race = race;

src/native/repromise.rei

@@ -23,6 +23,8 @@ let map: ('a => 'b, promise('a)) => promise('b);
 
 let on: ('a => unit, promise('a)) => unit;
 
+let tap: ('a => unit, promise('a)) => promise('a);
+
 let flatMap: ('a => promise('b), promise('a)) => promise('b);
 
 let all: list(promise('a)) => promise(list('a));
@@ -71,6 +73,12 @@ let onOk:
 let onError:
   ('e => unit, promise(result(_, 'e))) => unit;
 
+let tapOk:
+  ('a => unit, promise(result('a, 'e))) => promise(result('a, 'e));
+
+let tapError:
+  ('e => unit, promise(result('a, 'e))) => promise(result('a, 'e));
+
 let flatMapOk:
   ('a => promise(result('b, 'e)), promise(result('a, 'e))) =>
     promise(result('b, 'e));
@@ -97,6 +105,9 @@ let mapSome:
 let onSome:
   ('a => unit, promise(option('a))) => unit;
 
+let tapSome:
+  ('a => unit, promise(option('a))) => promise(option('a));
+
 let flatMapSome:
   ('a => promise(option('b)), promise(option('a))) => promise(option('b));
 
@@ -121,6 +132,8 @@ module Rejectable: {
 
   let on: ('a => unit, rejectable('a, _)) => unit;
 
+  let tap: ('a => unit, rejectable('a, 'e)) => rejectable('a, 'e);
+
   let catch:
     ('e => rejectable('a, 'e2), rejectable('a, 'e)) => rejectable('a, 'e2);
 

test/test_repromise.re

@@ -22,7 +22,14 @@ let basicTests = Framework.suite("basic", [
     Repromise.resolved(1)
     |> Repromise.on(n => correct := (n == 1));
     Repromise.resolved()
-    |> Repromise.map(() => correct^)
+    |> Repromise.map(() => correct^);
+  }),
+
+  test("tap", () => {
+    let correct = ref(false);
+    Repromise.resolved(1)
+    |> Repromise.tap(n => correct := (n == 1))
+    |> Repromise.map(n => n == 1 && correct^);
   }),
 
   test("flatMap", () => {
@@ -563,6 +570,34 @@ let resultTests = Framework.suite("result", [
     |> Repromise.map(n => n == 43);
   }),
 
+  test("tapOk, ok", () => {
+    let correct = ref(false);
+    Repromise.resolved(Ok(42))
+    |> Repromise.tapOk(n => correct := n == 42)
+    |> Repromise.map(result => result == Ok(42) && correct^);
+  }),
+
+  test("tapOk, error", () => {
+    let called = ref(false);
+    Repromise.resolved(Error(42))
+    |> Repromise.tapOk(_ => called := true)
+    |> Repromise.map(result => result == Error(42) && !called^);
+  }),
+
+  test("tapError, ok", () => {
+    let called = ref(false);
+    Repromise.resolved(Ok(42))
+    |> Repromise.tapError(_ => called := true)
+    |> Repromise.map(result => result == Ok(42) && !called^);
+  }),
+
+  test("onError, error", () => {
+    let correct = ref(false);
+    Repromise.resolved(Error(42))
+    |> Repromise.tapError(n => correct := n == 42)
+    |> Repromise.map(result => result == Error(42) && correct^);
+  }),
+
   test("flatMapOk, ok", () => {
     Repromise.resolved(Ok(42))
     |> Repromise.flatMapOk(n => Repromise.resolved(Ok(n + 1)))
@@ -647,6 +682,20 @@ let optionTests = Framework.suite("opton", [
     |> Repromise.map(() => !called^);
   }),
 
+  test("tapSome, some", () => {
+    let correct = ref(false);
+    Repromise.resolved(Some(42))
+    |> Repromise.tapSome(n => correct := n == 42)
+    |> Repromise.map(result => result == Some(42) && correct^);
+  }),
+
+  test("tapSome, none", () => {
+    let called = ref(false);
+    Repromise.resolved(None)
+    |> Repromise.tapSome(_ => called := true)
+    |> Repromise.map(result => result == None && !called^);
+  }),
+
   test("flatMapSome, some", () => {
     Repromise.resolved(Some(42))
     |> Repromise.flatMapSome(n => Repromise.resolved(Some(n + 1)))