refactor: of now works with Applicatives (#3272)

This change addresses the issue of `of` not being able to
work with Applicatives.

Fixes #3267

BREAKING CHANGE: `of` is now a binary function with a constructor as its first argument.

source/of.js

@@ -1,9 +1,12 @@
-import _curry1 from './internal/_curry1.js';
-import _of from './internal/_of.js';
-
+import _curry2 from './internal/_curry2.js';
 
 /**
- * Returns a singleton array containing the value provided.
+ * Given a constructor and a value, returns a new instance of that constructor
+ * containing the value.
+ *
+ * Dispatches to the `fantasy-land/of` method of the constructor first (if present)
+ * or to the `of` method last (if present). When neither are present, wraps the
+ * value in an array.
  *
  * Note this `of` is different from the ES6 `of`; See
  * https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/of
@@ -12,13 +15,24 @@ import _of from './internal/_of.js';
  * @memberOf R
  * @since v0.3.0
  * @category Function
- * @sig a -> [a]
- * @param {*} x any value
- * @return {Array} An array wrapping `x`.
+ * @sig (* -> {*}) -> a -> {a}
+ * @param {Object} Ctor A constructor
+ * @param {*} val any value
+ * @return {*} An instance of the `Ctor` wrapping `val`.
  * @example
  *
- *      R.of(null); //=> [null]
- *      R.of([42]); //=> [[42]]
+ *      R.of(Array, 42);   //=> [42]
+ *      R.of(Array, [42]); //=> [[42]]
+ *      R.of(Maybe, 42);   //=> Maybe.Just(42)
  */
-var of = _curry1(_of);
+var of = _curry2(function of(Ctor, val) {
+  return (
+    typeof Ctor['fantasy-land/of'] === 'function'
+      ? Ctor['fantasy-land/of'](val)
+      : typeof Ctor.of === 'function'
+        ? Ctor.of(val)
+        : [val]
+  );
+});
+
 export default of;

test/of.js

@@ -1,14 +1,19 @@
+var S = require('sanctuary');
+
 var R = require('../source/index.js');
 var eq = require('./shared/eq.js');
 
 
 describe('of', function() {
   it('returns its argument as an Array', function() {
-    eq(R.of(100), [100]);
-    eq(R.of([100]), [[100]]);
-    eq(R.of(null), [null]);
-    eq(R.of(undefined), [undefined]);
-    eq(R.of([]), [[]]);
+    eq(R.of(Array, 100), [100]);
+    eq(R.of(Array, [100]), [[100]]);
+    eq(R.of(Array, null), [null]);
+    eq(R.of(Array, undefined), [undefined]);
+    eq(R.of(Array, []), [[]]);
   });
 
+  it('dispatches to an available of method', function() {
+    eq(R.of(S.Maybe, 100), S.Just(100));
+  });
 });

test/sequence.js

@@ -4,33 +4,36 @@ var R = require('../source/index.js');
 var Id = require('./shared/Id.js');
 var eq = require('./shared/eq.js');
 
+var ofArray = R.of(Array);
+var ofEither = R.of(S.Either);
+var ofMaybe = R.of(S.Maybe);
 
 describe('sequence', function() {
 
   it('operates on a list of lists', function() {
-    eq(R.sequence(R.of, []), [[]]);
-    eq(R.sequence(R.of, [[], [1, 2, 3, 4]]), []);
-    eq(R.sequence(R.of, [[1], [2, 3, 4]]), [[1, 2], [1, 3], [1, 4]]);
-    eq(R.sequence(R.of, [[1, 2], [3, 4]]), [[1, 3], [1, 4], [2, 3], [2, 4]]);
-    eq(R.sequence(R.of, [[1, 2, 3], [4]]), [[1, 4], [2, 4], [3, 4]]);
-    eq(R.sequence(R.of, [[1, 2, 3, 4], []]), []);
+    eq(R.sequence(ofArray, []), [[]]);
+    eq(R.sequence(ofArray, [[], [1, 2, 3, 4]]), []);
+    eq(R.sequence(ofArray, [[1], [2, 3, 4]]), [[1, 2], [1, 3], [1, 4]]);
+    eq(R.sequence(ofArray, [[1, 2], [3, 4]]), [[1, 3], [1, 4], [2, 3], [2, 4]]);
+    eq(R.sequence(ofArray, [[1, 2, 3], [4]]), [[1, 4], [2, 4], [3, 4]]);
+    eq(R.sequence(ofArray, [[1, 2, 3, 4], []]), []);
   });
 
   it('operates on a list of applicatives', function() {
-    eq(R.sequence(S.Maybe.of, [S.Just(3), S.Just(4), S.Just(5)]), S.Just([3, 4, 5]));
-    eq(R.sequence(S.Maybe.of, [S.Just(3), S.Nothing(), S.Just(5)]), S.Nothing());
+    eq(R.sequence(ofMaybe, [S.Just(3), S.Just(4), S.Just(5)]), S.Just([3, 4, 5]));
+    eq(R.sequence(ofMaybe, [S.Just(3), S.Nothing(), S.Just(5)]), S.Nothing());
   });
 
   it('traverses left to right', function() {
-    eq(R.sequence(S.Either.of, [S.Right(1), S.Right(2)]), S.Right([1, 2]));
-    eq(R.sequence(S.Either.of, [S.Right(1), S.Left('XXX')]), S.Left('XXX'));
-    eq(R.sequence(S.Either.of, [S.Left('XXX'), S.Right(1)]), S.Left('XXX'));
-    eq(R.sequence(S.Either.of, [S.Left('XXX'), S.Left('YYY')]), S.Left('XXX'));
+    eq(R.sequence(ofEither, [S.Right(1), S.Right(2)]), S.Right([1, 2]));
+    eq(R.sequence(ofEither, [S.Right(1), S.Left('XXX')]), S.Left('XXX'));
+    eq(R.sequence(ofEither, [S.Left('XXX'), S.Right(1)]), S.Left('XXX'));
+    eq(R.sequence(ofEither, [S.Left('XXX'), S.Left('YYY')]), S.Left('XXX'));
   });
 
   it('dispatches to `sequence` method', function() {
     eq(R.sequence(Id, [Id(1), Id(2), Id(3)]), Id([1, 2, 3]));
-    eq(R.sequence(R.of, Id([1, 2, 3])), [Id(1), Id(2), Id(3)]);
+    eq(R.sequence(ofArray, Id([1, 2, 3])), [Id(1), Id(2), Id(3)]);
   });
 
 });

test/traverse.js

@@ -4,28 +4,32 @@ var R = require('../source/index.js');
 var Id = require('./shared/Id.js');
 var eq = require('./shared/eq.js');
 
+var ofArray = R.of(Array);
+var ofEither = R.of(S.Either);
+var ofMaybe = R.of(S.Maybe);
+
 
 describe('traverse', function() {
 
   it('operates on a list of lists', function() {
-    eq(R.traverse(R.of, R.map(R.add(10)), []), [[]]);
-    eq(R.traverse(R.of, R.map(R.add(10)), [[], [1, 2, 3, 4]]), []);
-    eq(R.traverse(R.of, R.map(R.add(10)), [[1], [2, 3, 4]]), [[11, 12], [11, 13], [11, 14]]);
-    eq(R.traverse(R.of, R.map(R.add(10)), [[1, 2], [3, 4]]), [[11, 13], [11, 14], [12, 13], [12, 14]]);
-    eq(R.traverse(R.of, R.map(R.add(10)), [[1, 2, 3], [4]]), [[11, 14], [12, 14], [13, 14]]);
-    eq(R.traverse(R.of, R.map(R.add(10)), [[1, 2, 3, 4], []]), []);
+    eq(R.traverse(ofArray, R.map(R.add(10)), []), [[]]);
+    eq(R.traverse(ofArray, R.map(R.add(10)), [[], [1, 2, 3, 4]]), []);
+    eq(R.traverse(ofArray, R.map(R.add(10)), [[1], [2, 3, 4]]), [[11, 12], [11, 13], [11, 14]]);
+    eq(R.traverse(ofArray, R.map(R.add(10)), [[1, 2], [3, 4]]), [[11, 13], [11, 14], [12, 13], [12, 14]]);
+    eq(R.traverse(ofArray, R.map(R.add(10)), [[1, 2, 3], [4]]), [[11, 14], [12, 14], [13, 14]]);
+    eq(R.traverse(ofArray, R.map(R.add(10)), [[1, 2, 3, 4], []]), []);
   });
 
   it('operates on a list of applicatives', function() {
-    eq(R.traverse(S.Maybe.of, R.map(R.add(10)), [S.Just(3), S.Just(4), S.Just(5)]), S.Just([13, 14, 15]));
-    eq(R.traverse(S.Maybe.of, R.map(R.add(10)), [S.Just(3), S.Nothing(), S.Just(5)]), S.Nothing());
+    eq(R.traverse(ofMaybe, R.map(R.add(10)), [S.Just(3), S.Just(4), S.Just(5)]), S.Just([13, 14, 15]));
+    eq(R.traverse(ofMaybe, R.map(R.add(10)), [S.Just(3), S.Nothing(), S.Just(5)]), S.Nothing());
   });
 
   it('traverses left to right', function() {
-    eq(R.traverse(S.Either.of, R.identity, [S.Right(1), S.Right(2)]), S.Right([1, 2]));
-    eq(R.traverse(S.Either.of, R.identity, [S.Right(1), S.Left('XXX')]), S.Left('XXX'));
-    eq(R.traverse(S.Either.of, R.identity, [S.Left('XXX'), S.Right(1)]), S.Left('XXX'));
-    eq(R.traverse(S.Either.of, R.identity, [S.Left('XXX'), S.Left('YYY')]), S.Left('XXX'));
+    eq(R.traverse(ofEither, R.identity, [S.Right(1), S.Right(2)]), S.Right([1, 2]));
+    eq(R.traverse(ofEither, R.identity, [S.Right(1), S.Left('XXX')]), S.Left('XXX'));
+    eq(R.traverse(ofEither, R.identity, [S.Left('XXX'), S.Right(1)]), S.Left('XXX'));
+    eq(R.traverse(ofEither, R.identity, [S.Left('XXX'), S.Left('YYY')]), S.Left('XXX'));
   });
 
   it('dispatches to `traverse` method', function() {

test/unless.js

@@ -2,19 +2,21 @@ var R = require('../source/index.js');
 var eq = require('./shared/eq.js');
 var _isArrayLike = require('../source/internal/_isArrayLike.js');
 
+var ofArray = R.of(Array);
+
 
 describe('unless', function() {
   it('calls the whenFalse function if the validator returns a falsy value', function() {
-    eq(R.unless(_isArrayLike, R.of)(10), [10]);
+    eq(R.unless(_isArrayLike, ofArray)(10), [10]);
   });
 
   it('returns the argument unmodified if the validator returns a truthy value', function() {
-    eq(R.unless(_isArrayLike, R.of)([10]), [10]);
+    eq(R.unless(_isArrayLike, ofArray)([10]), [10]);
   });
 
   it('returns a curried function', function() {
-    eq(R.unless(_isArrayLike)(R.of)(10), [10]);
-    eq(R.unless(_isArrayLike)(R.of)([10]), [10]);
+    eq(R.unless(_isArrayLike)(ofArray)(10), [10]);
+    eq(R.unless(_isArrayLike)(ofArray)([10]), [10]);
   });
 
 });