Support for await and yield in pipelines (#9401)

packages/babel-plugin-proposal-pipeline-operator/src/minimalVisitor.js

@@ -1,8 +1,7 @@
 import { types as t } from "@babel/core";
 
 const minimalVisitor = {
-  BinaryExpression: {
-    exit(path) {
+  BinaryExpression(path) {
     const { scope } = path;
     const { node } = path;
     const { operator, left } = node;
@@ -49,7 +48,6 @@ const minimalVisitor = {
       ]),
     );
   },
-  },
 };
 
 export default minimalVisitor;

packages/babel-plugin-proposal-pipeline-operator/src/smartVisitor.js

@@ -1,41 +1,47 @@
 import { types as t } from "@babel/core";
-import minimalVisitor from "./minimalVisitor";
 
 const updateTopicReferenceVisitor = {
   PipelinePrimaryTopicReference(path) {
     path.replaceWith(this.topicId);
   },
-  AwaitExpression(path) {
-    throw path.buildCodeFrameError(
-      "await is not supported inside pipeline expressions yet",
-    );
-  },
-  YieldExpression(path) {
-    throw path.buildCodeFrameError(
-      "yield is not supported inside pipeline expressions yet",
-    );
-  },
   PipelineTopicExpression(path) {
     path.skip();
   },
 };
 
 const smartVisitor = {
-  ...minimalVisitor,
-  PipelineTopicExpression(path) {
-    const topicId = path.scope.generateUidIdentifier("topic");
+  BinaryExpression(path) {
+    const { scope } = path;
+    const { node } = path;
+    const { operator, left, right } = node;
+    if (operator !== "|>") return;
 
-    path.traverse(updateTopicReferenceVisitor, { topicId });
+    const placeholder = scope.generateUidIdentifierBasedOnNode(left);
+    scope.push({ id: placeholder });
 
-    const arrowFunctionExpression = t.arrowFunctionExpression(
-      [topicId],
-      path.node.expression,
+    let call;
+    if (t.isPipelineTopicExpression(right)) {
+      path
+        .get("right")
+        .traverse(updateTopicReferenceVisitor, { topicId: placeholder });
+
+      call = right.expression;
+    } else {
+      // PipelineBareFunction
+      let callee = right.callee;
+      if (t.isIdentifier(callee, { name: "eval" })) {
+        callee = t.sequenceExpression([t.numericLiteral(0), callee]);
+      }
+
+      call = t.callExpression(callee, [t.cloneNode(placeholder)]);
+    }
+
+    path.replaceWith(
+      t.sequenceExpression([
+        t.assignmentExpression("=", t.cloneNode(placeholder), left),
+        call,
+      ]),
     );
-
-    path.replaceWith(arrowFunctionExpression);
-  },
-  PipelineBareFunction(path) {
-    path.replaceWith(path.node.callee);
   },
 };
 

packages/babel-plugin-proposal-pipeline-operator/test/fixtures/minimal/arrow-functions/output.js

@@ -1,6 +1,6 @@
-var _ref, _ref2, _sum;
+var _sum, _ref, _ref2;
 
-var result = (_sum = (_ref2 = (_ref = [5, 10], _ref.map(x => x * 2)), _ref2.reduce((a, b) => a + b)), _sum + 1);
+var result = (_sum = (_ref = (_ref2 = [5, 10], _ref2.map(x => x * 2)), _ref.reduce((a, b) => a + b)), _sum + 1);
 expect(result).toBe(31);
 
 var inc = x => x + 1;
@@ -8,7 +8,7 @@ var inc = x => x + 1;
 var double = x => x * 2;
 
 var result2 = [4, 9].map(x => {
-  var _x, _ref3;
+  var _ref3, _x;
 
   return _ref3 = (_x = x, inc(_x)), double(_ref3);
 });

packages/babel-plugin-proposal-pipeline-operator/test/fixtures/minimal/async-arrow/exec.js

@@ -8,6 +8,6 @@ var result = 1
   |> (async (x) => await x + 1)
   |> then((x) => x + 1);
 
-result.then(val => {
+return result.then(val => {
   expect(val).toBe(3);
 });

packages/babel-plugin-proposal-pipeline-operator/test/fixtures/minimal/async-arrow/output.js

@@ -1,4 +1,4 @@
-var _, _ref;
+var _ref, _;
 
 function then(fn) {
   return async value => {

packages/babel-plugin-proposal-pipeline-operator/test/fixtures/minimal/chaining/output.js

@@ -1,4 +1,4 @@
-var _, _ref;
+var _ref, _;
 
 var inc = x => x + 1;
 

packages/babel-plugin-proposal-pipeline-operator/test/fixtures/minimal/deoptimize-multi-param-arrow/output.js

@@ -1,4 +1,4 @@
-var _a, _ref;
+var _ref, _a;
 
 var a = 1,
     b = 2,

packages/babel-plugin-proposal-pipeline-operator/test/fixtures/minimal/options.json

@@ -1,3 +1,6 @@
 {
-  "plugins": [["proposal-pipeline-operator", { "proposal": "minimal" }]]
+  "plugins": [["proposal-pipeline-operator", { "proposal": "minimal" }]],
+  "parserOpts": {
+    "allowReturnOutsideFunction": true
+  }
 }

packages/babel-plugin-proposal-pipeline-operator/test/fixtures/minimal/precedence/output.js

@@ -1,4 +1,4 @@
-var _ref, _, _ref2;
+var _ref, _ref2, _;
 
 var inc = x => x + 1;
 

packages/babel-plugin-proposal-pipeline-operator/test/fixtures/smart+arrow/await/exec.js

@@ -0,0 +1,13 @@
+const triple = (x) => x * 3;
+
+async function myFunction(n) {
+  return n
+    |> Math.abs
+    |> Promise.resolve(#)
+    |> await #
+    |> triple;
+}
+
+return myFunction(-7).then(result => {
+  expect(result).toBe(21);
+});

packages/babel-plugin-proposal-pipeline-operator/test/fixtures/smart+arrow/await/options.json

@@ -0,0 +1,6 @@
+{
+  "parserOpts": {
+    "allowReturnOutsideFunction": true
+  },
+  "minNodeVersion": "8.0.0"
+}

packages/babel-plugin-proposal-pipeline-operator/test/fixtures/smart+arrow/options.json

@@ -0,0 +1,9 @@
+{
+  "plugins": [
+    ["proposal-pipeline-operator", { "proposal": "smart" }],
+    "transform-arrow-functions"
+  ],
+  "parserOpts": {
+    "allowReturnOutsideFunction": true
+  }
+}

packages/babel-plugin-proposal-pipeline-operator/test/fixtures/smart/await/exec.js

@@ -0,0 +1,13 @@
+const triple = (x) => x * 3;
+
+async function myFunction(n) {
+  return n
+    |> Math.abs
+    |> Promise.resolve(#)
+    |> await #
+    |> triple;
+}
+
+return myFunction(-7).then(result => {
+  expect(result).toBe(21);
+});

packages/babel-plugin-proposal-pipeline-operator/test/fixtures/smart/await/input.js

@@ -1,5 +1,6 @@
-async function myFunction() {
-  const value = -5.9
-  |> abs
-  |> await Math.floor(#);
+async function myFunction(n) {
+  return n
+    |> Math.abs
+    |> Promise.resolve(#)
+    |> await #;
 }

packages/babel-plugin-proposal-pipeline-operator/test/fixtures/smart/await/options.json

@@ -1,4 +1,9 @@
 {
-  "throws": "await is not supported inside pipeline expressions yet",
-  "plugins": [["proposal-pipeline-operator", { "proposal": "smart" }]]
+  "plugins": [
+    ["proposal-pipeline-operator", { "proposal": "smart" }]
+  ],
+  "parserOpts": {
+    "allowReturnOutsideFunction": true
+  },
+  "minNodeVersion": "8.0.0"
 }

packages/babel-plugin-proposal-pipeline-operator/test/fixtures/smart/await/output.js

@@ -0,0 +1,5 @@
+async function myFunction(n) {
+  var _ref, _ref2, _n;
+
+  return _ref = (_ref2 = (_n = n, Math.abs(_n)), Promise.resolve(_ref2)), await _ref;
+}

packages/babel-plugin-proposal-pipeline-operator/test/fixtures/smart/bare-function/output.js

@@ -1,4 +1,4 @@
 var _ref, _ref2;
 
 const abs = Math.abs;
-const value = (_ref2 = (_ref = -5.9, abs(_ref)), Math.floor(_ref2));
+const value = (_ref = (_ref2 = -5.9, abs(_ref2)), Math.floor(_ref));

packages/babel-plugin-proposal-pipeline-operator/test/fixtures/smart/basic/output.js

@@ -1,3 +1,3 @@
-var _topic2, _topic4, _topic6;
+var _ref, _ref2, _;
 
-var result = (_topic6 = (_topic4 = (_topic2 = 5, _topic2 + 1), _topic4 + _topic4), Math.pow((x => x * 7)(_topic6), 2));
+var result = (_ref = (_ref2 = (_ = 5, _ + 1), _ref2 + _ref2), Math.pow((x => x * 7)(_ref), 2));

packages/babel-plugin-proposal-pipeline-operator/test/fixtures/smart/for-init/exec.js

@@ -0,0 +1,5 @@
+let sum = 0;
+for (var i = 0 |> #; i <= 10; i++) 
+  sum = sum + i;
+
+expect(sum).toBe(10 + 9 + 8 + 7 + 6 + 5 + 4 + 3 + 2 + 1)

packages/babel-plugin-proposal-pipeline-operator/test/fixtures/smart/for-init/input.js

@@ -0,0 +1,5 @@
+let sum = 0;
+for (var i = 0 |> #; i <= 10; i++) 
+  sum = sum + i;
+
+expect(sum).toBe(10 + 9 + 8 + 7 + 6 + 5 + 4 + 3 + 2 + 1)

packages/babel-plugin-proposal-pipeline-operator/test/fixtures/smart/for-init/output.js

@@ -0,0 +1,9 @@
+let sum = 0;
+
+for (var i = (_ = 0, _); i <= 10; i++) {
+  var _;
+
+  sum = sum + i;
+}
+
+expect(sum).toBe(10 + 9 + 8 + 7 + 6 + 5 + 4 + 3 + 2 + 1);

packages/babel-plugin-proposal-pipeline-operator/test/fixtures/smart/for-update/exec.js

@@ -0,0 +1,6 @@
+let sum = 0;
+for (var i = 0; i <= 10; i = i |> # + 1) {
+  sum = sum + i;
+}
+
+expect(sum).toBe(10 + 9 + 8 + 7 + 6 + 5 + 4 + 3 + 2 + 1)

packages/babel-plugin-proposal-pipeline-operator/test/fixtures/smart/for-update/input.js

@@ -0,0 +1,6 @@
+let sum = 0;
+for (var i = 0; i <= 10; i = i |> # + 1) {
+  sum = sum + i;
+}
+
+expect(sum).toBe(10 + 9 + 8 + 7 + 6 + 5 + 4 + 3 + 2 + 1)

packages/babel-plugin-proposal-pipeline-operator/test/fixtures/smart/for-update/output.js

@@ -0,0 +1,9 @@
+let sum = 0;
+
+for (var i = 0; i <= 10; i = (_i = i, _i + 1)) {
+  var _i;
+
+  sum = sum + i;
+}
+
+expect(sum).toBe(10 + 9 + 8 + 7 + 6 + 5 + 4 + 3 + 2 + 1);

packages/babel-plugin-proposal-pipeline-operator/test/fixtures/smart/for/exec.js

@@ -0,0 +1,5 @@
+let sum = 0;
+for (var i = 0; i |> # <= 10; i++) 
+  sum = sum + i;
+
+expect(sum).toBe(10 + 9 + 8 + 7 + 6 + 5 + 4 + 3 + 2 + 1)

packages/babel-plugin-proposal-pipeline-operator/test/fixtures/smart/for/input.js

@@ -0,0 +1,5 @@
+let sum = 0;
+for (var i = 0; (i |> # <= 10); ++i) 
+  sum = sum + i;
+
+expect(sum).toBe(10 + 9 + 8 + 7 + 6 + 5 + 4 + 3 + 2 + 1)

packages/babel-plugin-proposal-pipeline-operator/test/fixtures/smart/for/output.js

@@ -0,0 +1,9 @@
+let sum = 0;
+
+for (var i = 0; _i = i, _i <= 10; ++i) {
+  var _i;
+
+  sum = sum + i;
+}
+
+expect(sum).toBe(10 + 9 + 8 + 7 + 6 + 5 + 4 + 3 + 2 + 1);

packages/babel-plugin-proposal-pipeline-operator/test/fixtures/smart/if/input.js

@@ -0,0 +1,4 @@
+if (v |> e |> f)
+  g() |> h(#, #+1) |> i;
+else
+  j();

packages/babel-plugin-proposal-pipeline-operator/test/fixtures/smart/if/output.js

@@ -0,0 +1,3 @@
+var _ref, _v, _ref2, _g;
+
+if (_ref = (_v = v, e(_v)), f(_ref)) _ref2 = (_g = g(), h(_g, _g + 1)), i(_ref2);else j();

packages/babel-plugin-proposal-pipeline-operator/test/fixtures/smart/indirect-eval/exec.js

@@ -0,0 +1,7 @@
+(function() {
+  'use strict';
+  var result = '(function() { return this; })()'
+    |> eval;
+
+  expect(result).not.toBeUndefined();
+})();

packages/babel-plugin-proposal-pipeline-operator/test/fixtures/smart/indirect-eval/input.js

@@ -0,0 +1,7 @@
+(function() {
+  'use strict';
+  var result = '(function() { return this; })()'
+    |> eval;
+
+  expect(result).not.toBeUndefined();
+})();

packages/babel-plugin-proposal-pipeline-operator/test/fixtures/smart/indirect-eval/output.js

@@ -0,0 +1,8 @@
+(function () {
+  'use strict';
+
+  var _functionReturn;
+
+  var result = (_functionReturn = '(function() { return this; })()', (0, eval)(_functionReturn));
+  expect(result).not.toBeUndefined();
+})();

packages/babel-plugin-proposal-pipeline-operator/test/fixtures/smart/nested/output.js

@@ -1,7 +1,7 @@
-var _topic2, _topic8;
+var _ref, _;
 
-var result = (_topic8 = (_topic2 = 5, Math.pow(_topic2, 2)), [10, 20, 30, 40, 50].filter(n => {
-  var _topic5, _topic7;
+var result = (_ref = (_ = 5, Math.pow(_, 2)), [10, 20, 30, 40, 50].filter(n => {
+  var _ref2, _ref3;
 
-  return _topic7 = (_topic5 = _topic8, n > _topic5), !_topic7;
+  return _ref2 = (_ref3 = _ref, n > _ref3), !_ref2;
 }));

packages/babel-plugin-proposal-pipeline-operator/test/fixtures/smart/object-literal/output.js

@@ -1,10 +1,10 @@
-var _ref, _topic2, _ref2;
+var _ref, _ref2, _ref3;
 
 function area(rect) {
   return rect.width * rect.height;
 }
 
-const result = (_ref2 = (_topic2 = (_ref = -5, Math.abs(_ref)), {
-  width: _topic2,
-  height: _topic2 + 3
-}), area(_ref2));
+const result = (_ref = (_ref2 = (_ref3 = -5, Math.abs(_ref3)), {
+  width: _ref2,
+  height: _ref2 + 3
+}), area(_ref));

packages/babel-plugin-proposal-pipeline-operator/test/fixtures/smart/options.json

@@ -1,3 +1,8 @@
 {
-  "plugins": [["proposal-pipeline-operator", { "proposal": "smart" }]]
+  "plugins": [
+    ["proposal-pipeline-operator", { "proposal": "smart" }]
+  ],
+  "parserOpts": {
+    "allowReturnOutsideFunction": true
+  }
 }

packages/babel-plugin-proposal-pipeline-operator/test/fixtures/smart/topic-as-callee/input.js

@@ -1 +1 @@
-v |> #.method |> f;
+v |> #.method() |> f;

packages/babel-plugin-proposal-pipeline-operator/test/fixtures/smart/topic-as-callee/output.js

@@ -1,3 +1,3 @@
-var _topic2, _ref;
+var _ref, _v;
 
-_ref = (_topic2 = v, _topic2.method), f(_ref);
+_ref = (_v = v, _v.method()), f(_ref);

packages/babel-plugin-proposal-pipeline-operator/test/fixtures/smart/topic-inside-arrow-function/output.js

@@ -1,7 +1,7 @@
-var _ref, _topic2, _topic4, _ref2;
+var _ref, _ref2, _ref3, _ref4;
 
-const result = (_ref2 = (_topic4 = (_topic2 = (_ref = -2.2 // -2.2
-, Math.floor(_ref) // -3
-), () => Math.pow(_topic2, 5) // () => -243
-), _topic4() // -243
-), Math.sign(_ref2)); // -1
+const result = (_ref = (_ref2 = (_ref3 = (_ref4 = -2.2 // -2.2
+, Math.floor(_ref4) // -3
+), () => Math.pow(_ref3, 5) // () => -243
+), _ref2() // -243
+), Math.sign(_ref)); // -1

packages/babel-plugin-proposal-pipeline-operator/test/fixtures/smart/while/exec.js

@@ -0,0 +1,7 @@
+let i = 0
+let sum = 0
+
+while (i |> (i = # + 1) |> # <= 10)
+  sum = sum + i;
+
+expect(sum).toBe(10 + 9 + 8 + 7 + 6 + 5 + 4 + 3 + 2 + 1)

packages/babel-plugin-proposal-pipeline-operator/test/fixtures/smart/while/input.js

@@ -0,0 +1,7 @@
+let i = 0
+let sum = 0
+
+while (i |> (i = # + 1) |> # <= 10)
+  sum = sum + i;
+
+expect(sum).toBe(10 + 9 + 8 + 7 + 6 + 5 + 4 + 3 + 2 + 1)

packages/babel-plugin-proposal-pipeline-operator/test/fixtures/smart/while/output.js

@@ -0,0 +1,10 @@
+let i = 0;
+let sum = 0;
+
+while (_ref = (_i = i, i = _i + 1), _ref <= 10) {
+  var _ref, _i;
+
+  sum = sum + i;
+}
+
+expect(sum).toBe(10 + 9 + 8 + 7 + 6 + 5 + 4 + 3 + 2 + 1);

packages/babel-plugin-proposal-pipeline-operator/test/fixtures/smart/yield/exec.js

@@ -0,0 +1,13 @@
+function *myGenerator(n) {
+  return n
+  |> (yield #)
+  |> Math.abs;
+}
+
+const myIterator = myGenerator(15);
+
+const yieldedValue = myIterator.next().value;
+const returnedValue = myIterator.next(-30).value;
+
+expect(yieldedValue).toBe(15);
+expect(returnedValue).toBe(30);

packages/babel-plugin-proposal-pipeline-operator/test/fixtures/smart/yield/input.js

@@ -1,5 +1,5 @@
-function *myGenerator() {
-  return v
+function *myGenerator(n) {
+  return n
     |> (yield #)
-  |> g;
+    |> Math.abs;
 }

packages/babel-plugin-proposal-pipeline-operator/test/fixtures/smart/yield/options.json

@@ -1,4 +0,0 @@
-{
-  "throws": "yield is not supported inside pipeline expressions yet",
-  "plugins": [["proposal-pipeline-operator", { "proposal": "smart" }]]
-}

packages/babel-plugin-proposal-pipeline-operator/test/fixtures/smart/yield/output.js

@@ -0,0 +1,5 @@
+function* myGenerator(n) {
+  var _ref, _n;
+
+  return _ref = (_n = n, yield _n), Math.abs(_ref);
+}