Do expressions transform for switch statements (#10070)

* lint fix

* switch inside do expression

* review comments

* review comments

* make min diff

* adding more test

* review changes

* review changes

* handle block statement and added more test cases

* fix implementation and add more test cases

* fix last swtich case

* disable block fallthrough case

* fix nitpick reviews

packages/babel-plugin-proposal-do-expressions/test/fixtures/do-expression-switch-case/.fallthrough-multiblock/exec.js

@@ -0,0 +1,36 @@
+// `blockExpressions` before `break` is hard to deal with
+// https://github.com/babel/babel/pull/10070#discussion_r296048106
+const x = (n) => do {
+  switch (n) {
+    case 0: 
+      { "a"; }
+      { "b"; };
+    case 1: 
+      { "c"; }
+      break;
+      { "d"; };
+    case 2: 
+      "a";
+      "b";
+    case 3:
+      {}
+      { break; }
+    case 4:
+      { "d"; }
+      { "e"; }
+    case 5:
+      "f";
+    case 6:
+      {}
+    case 7:
+  }
+}
+
+expect(x(0)).toBe('c')
+expect(x(1)).toBe('c')
+expect(x(2)).toBeUndefined()
+expect(x(3)).toBeUndefined()
+expect(x(4)).toBe('f')
+expect(x(5)).toBe('f')
+expect(x(6)).toBeUndefined()
+expect(x(7)).toBeUndefined()

packages/babel-plugin-proposal-do-expressions/test/fixtures/do-expression-switch-case/.fallthrough-multiblock/input.js

@@ -0,0 +1,25 @@
+const x = (n) => do {
+  switch (n) {
+    case 0: 
+      { "a"; }
+      { "b"; };
+    case 1: 
+      { "c"; }
+      break;
+      { "d"; };
+    case 2: 
+      "a";
+      "b";
+    case 3:
+      {}
+      { break; }
+    case 4:
+      { "a"; }
+      { "b"; }
+    case 5:
+      "c";
+    case 6:
+      {}
+    case 7:
+  }
+}

packages/babel-plugin-proposal-do-expressions/test/fixtures/do-expression-switch-case/declaration-before-break/input.js

@@ -0,0 +1,9 @@
+const x = (n) => do {
+  switch (n) {
+    case 0: 
+    case 6: 
+      const b = 1;
+      break;
+    default: 'bar';
+  }
+}

packages/babel-plugin-proposal-do-expressions/test/fixtures/do-expression-switch-case/declaration-before-break/output.js

@@ -0,0 +1,11 @@
+const x = n => function () {
+  switch (n) {
+    case 0:
+    case 6:
+      const b = 1;
+      return void 0;
+
+    default:
+      return 'bar';
+  }
+}();

packages/babel-plugin-proposal-do-expressions/test/fixtures/do-expression-switch-case/empty-case-block/input.js

@@ -0,0 +1,7 @@
+const x = () => do {
+  switch (new Date().getDay()) {
+    case 0:
+      break;
+    default: "weekday 🚴"
+  }
+}

packages/babel-plugin-proposal-do-expressions/test/fixtures/do-expression-switch-case/empty-case-block/output.js

@@ -0,0 +1,9 @@
+const x = () => function () {
+  switch (new Date().getDay()) {
+    case 0:
+      return void 0;
+
+    default:
+      return "weekday 🚴";
+  }
+}();

packages/babel-plugin-proposal-do-expressions/test/fixtures/do-expression-switch-case/fallthrough-block-last/exec.js

@@ -0,0 +1,26 @@
+const x = (n) => do {
+  switch (n) {
+    case 0: {
+      'a';
+    }
+    case 1: {
+      'b';
+      break;
+    }
+    default: {
+      'd';
+    }
+    case 2: {
+      'c';
+    }
+    case 3:
+    case 4:
+  }
+}
+
+expect(x(0)).toBe('b');
+expect(x(1)).toBe('b');
+expect(x(2)).toBe('c');
+expect(x(3)).toBeUndefined();
+expect(x(4)).toBeUndefined();
+expect(x(5)).toBe('c');

packages/babel-plugin-proposal-do-expressions/test/fixtures/do-expression-switch-case/fallthrough-block-last/input.js

@@ -0,0 +1,19 @@
+const x = (n) => do {
+  switch (n) {
+    case 0: {
+      'a';
+    }
+    case 1: {
+      'b';
+      break;
+    }
+    default: {
+      'd';
+    }
+    case 2: {
+      'c';
+    }
+    case 3:
+    case 4:
+  }
+}

packages/babel-plugin-proposal-do-expressions/test/fixtures/do-expression-switch-case/fallthrough-block-last/output.js

@@ -0,0 +1,26 @@
+const x = n => function () {
+  switch (n) {
+    case 0:
+      {
+        'a';
+      }
+
+    case 1:
+      {
+        return 'b';
+      }
+
+    default:
+      {
+        'd';
+      }
+
+    case 2:
+      {
+        return 'c';
+      }
+
+    case 3:
+    case 4:
+  }
+}();

packages/babel-plugin-proposal-do-expressions/test/fixtures/do-expression-switch-case/fallthrough-block/exec.js

@@ -0,0 +1,30 @@
+const x = (n) => do {
+  switch (n) {
+    case 0: {
+      'a';
+    }
+    case 1: {
+      'b';
+      break;
+    }
+    case 2: {
+      'c';
+      break;
+    }
+    case 3: {
+      break;
+    }
+    case 4: {
+      'd';
+      'e';
+    }
+    default: 'f';
+  }
+}
+
+expect(x(0)).toBe('b');
+expect(x(1)).toBe('b');
+expect(x(2)).toBe('c');
+expect(x(3)).toBeUndefined();
+expect(x(4)).toBe('f');
+expect(x(5)).toBe('f');

packages/babel-plugin-proposal-do-expressions/test/fixtures/do-expression-switch-case/fallthrough-block/input.js

@@ -0,0 +1,23 @@
+const x = (n) => do {
+  switch (n) {
+    case 0: {
+      'a';
+    }
+    case 1: {
+      'b';
+      break;
+    }
+    case 2: {
+      'c';
+      break;
+    }
+    case 3: {
+      break;
+    }
+    case 4: {
+      'd';
+      'e';
+    }
+    default: 'f';
+  }
+}

packages/babel-plugin-proposal-do-expressions/test/fixtures/do-expression-switch-case/fallthrough-block/output.js

@@ -0,0 +1,30 @@
+const x = n => function () {
+  switch (n) {
+    case 0:
+      {
+        'a';
+      }
+
+    case 1:
+      {
+        return 'b';
+      }
+
+    case 2:
+      {
+        return 'c';
+      }
+
+    case 3:
+      return void 0;
+
+    case 4:
+      {
+        'd';
+        'e';
+      }
+
+    default:
+      return 'f';
+  }
+}();

packages/babel-plugin-proposal-do-expressions/test/fixtures/do-expression-switch-case/fallthrough-last/exec.js

@@ -0,0 +1,21 @@
+const x = (n) => do {
+  switch (n) {
+    case 0: 
+      'a';
+    case 1: 
+      'b';
+      break;
+    default: 'd';
+    case 2:
+      'c';
+    case 3:
+    case 4:
+  }
+}
+
+expect(x(0)).toBe('b');
+expect(x(1)).toBe('b');
+expect(x(2)).toBe('c');
+expect(x(3)).toBeUndefined();
+expect(x(4)).toBeUndefined();
+expect(x(5)).toBe('c');

packages/babel-plugin-proposal-do-expressions/test/fixtures/do-expression-switch-case/fallthrough-last/input.js

@@ -0,0 +1,14 @@
+const x = (n) => do {
+  switch (n) {
+    case 0: 
+      'a';
+    case 1: 
+      'b';
+      break;
+    default: 'd';
+    case 2:
+      'c';
+    case 3:
+    case 4:
+  }
+}

packages/babel-plugin-proposal-do-expressions/test/fixtures/do-expression-switch-case/fallthrough-last/output.js

@@ -0,0 +1,18 @@
+const x = n => function () {
+  switch (n) {
+    case 0:
+      'a';
+
+    case 1:
+      return 'b';
+
+    default:
+      'd';
+
+    case 2:
+      return 'c';
+
+    case 3:
+    case 4:
+  }
+}();

packages/babel-plugin-proposal-do-expressions/test/fixtures/do-expression-switch-case/fallthrough/exec.js

@@ -0,0 +1,25 @@
+const x = (n) => do {
+  switch (n) {
+    case 0: 
+      'a';
+    case 1: 
+      'b';
+      break;
+    case 2:
+      'c';
+      break;
+    case 3:
+      break;
+    case 4:
+      'd';
+      'e';
+    default: 'f';
+  }
+}
+
+expect(x(0)).toBe('b');
+expect(x(1)).toBe('b');
+expect(x(2)).toBe('c');
+expect(x(3)).toBeUndefined();
+expect(x(4)).toBe('f');
+expect(x(5)).toBe('f');

packages/babel-plugin-proposal-do-expressions/test/fixtures/do-expression-switch-case/fallthrough/input.js

@@ -0,0 +1,18 @@
+const x = (n) => do {
+  switch (n) {
+    case 0: 
+      'a';
+    case 1: 
+      'b';
+      break;
+    case 2:
+      'c';
+      break;
+    case 3:
+      break;
+    case 4:
+      'd';
+      'e';
+    default: 'f';
+  }
+}

packages/babel-plugin-proposal-do-expressions/test/fixtures/do-expression-switch-case/fallthrough/output.js

@@ -0,0 +1,22 @@
+const x = n => function () {
+  switch (n) {
+    case 0:
+      'a';
+
+    case 1:
+      return 'b';
+
+    case 2:
+      return 'c';
+
+    case 3:
+      return void 0;
+
+    case 4:
+      'd';
+      'e';
+
+    default:
+      return 'f';
+  }
+}();