feat: should support passing object slots via JSX children (#204)

* feat: should support passing object slots via JSX children

* feat: add unit test

* feat: remove `cloneDeep` of `isSlot`

* chore(deps): add `@babel/template`

packages/babel-plugin-jsx/package.json

@@ -11,11 +11,10 @@
     "url": "git+https://github.com/vuejs/jsx-next.git"
   },
   "scripts": {
-    "dev": "npm run build && webpack-dev-server",
     "build": "tsc",
     "lint": "eslint 'src/*.ts'",
-    "test": "npm run build && jest --coverage",
-    "prepublishOnly": "npm run build"
+    "test": "yarn build && jest --coverage",
+    "prepublishOnly": "yarn build"
   },
   "bugs": {
     "url": "https://github.com/vuejs/jsx-next/issues"
@@ -26,6 +25,7 @@
   "dependencies": {
     "@babel/helper-module-imports": "^7.0.0",
     "@babel/plugin-syntax-jsx": "^7.0.0",
+    "@babel/template": "^7.0.0",
     "@babel/traverse": "^7.0.0",
     "@babel/types": "^7.0.0",
     "@vue/babel-helper-vue-transform-on": "^1.0.0-rc.2",

packages/babel-plugin-jsx/src/index.ts

@@ -1,5 +1,6 @@
 import * as t from '@babel/types';
 import * as BabelCore from '@babel/core';
+import template from '@babel/template';
 import syntaxJsx from '@babel/plugin-syntax-jsx';
 import { addNamed, isModule, addNamespace } from '@babel/helper-module-imports';
 import { NodePath } from '@babel/traverse';
@@ -23,7 +24,6 @@ export type ExcludesBoolean = <T>(x: T | false | true) => x is T;
 
 const hasJSX = (parentPath: NodePath) => {
   let fileHasJSX = false;
-
   parentPath.traverse({
     JSXElement(path) { // skip ts error
       fileHasJSX = true;
@@ -62,6 +62,7 @@ export default ({ types }: typeof BabelCore) => ({
             'resolveDirective',
             'mergeProps',
             'createTextVNode',
+            'isVNode',
           ];
           if (isModule(path)) {
             // import { createVNode } from "vue";
@@ -83,6 +84,24 @@ export default ({ types }: typeof BabelCore) => ({
                 return identifier;
               });
             });
+            state.set('@vue/babel-plugin-jsx/runtimeIsSlot', () => {
+              if (importMap.runtimeIsSlot) {
+                return importMap.runtimeIsSlot;
+              }
+              const { name: isVNodeName } = state.get('isVNode')();
+              const isSlot = path.scope.generateUidIdentifier('isSlot');
+              const ast = template.ast`
+                function ${isSlot.name}(s) {
+                  return typeof s === 'function' || (Object.prototype.toString.call(s) === '[object Object]' && !${isVNodeName}(s));
+                }
+              `;
+              const lastImport = (path.get('body') as NodePath[]).filter((p) => p.isImportDeclaration()).pop();
+              if (lastImport) {
+                lastImport.insertAfter(ast);
+              }
+              importMap.runtimeIsSlot = isSlot;
+              return isSlot;
+            });
           } else {
             // var _vue = require('vue');
             let sourceName = '';

packages/babel-plugin-jsx/src/transform-vue-jsx.ts

@@ -83,12 +83,10 @@ const transformJSXElement = (
 
   const slotFlag = path.getData('slotFlag') || SlotFlags.STABLE;
 
-  const createVNode = t.callExpression(createIdentifier(state, 'createVNode'), [
-    tag,
-    props,
-    (children.length || slots) ? (
-      isComponent
-        ? t.objectExpression([
+  let VNodeChild;
+
+  if (children.length > 1 || slots) {
+    VNodeChild = isComponent ? t.objectExpression([
       !!children.length && t.objectProperty(
         t.identifier('default'),
         t.arrowFunctionExpression([], t.arrayExpression(buildIIFE(path, children))),
@@ -102,9 +100,82 @@ const transformJSXElement = (
         t.identifier('_'),
         t.numericLiteral(slotFlag),
       ),
-        ].filter(Boolean as any))
-        : t.arrayExpression(children)
-    ) : t.nullLiteral(),
+    ].filter(Boolean as any)) : t.arrayExpression(children);
+  } else if (children.length === 1) {
+    const child = children[0];
+    if (t.isIdentifier(child)) {
+      VNodeChild = t.conditionalExpression(
+        t.callExpression(state.get('@vue/babel-plugin-jsx/runtimeIsSlot')(), [child]),
+        child,
+        t.objectExpression([
+          t.objectProperty(
+            t.identifier('default'),
+            t.arrowFunctionExpression([], t.arrayExpression(buildIIFE(path, [child]))),
+          ),
+          optimize && t.objectProperty(
+            t.identifier('_'),
+            t.numericLiteral(slotFlag),
+          ) as any,
+        ].filter(Boolean)),
+      );
+    } else if (
+      t.isCallExpression(child) && child.loc && isComponent
+    ) { // the element was generated and doesn't have location information
+      const slotId = path.scope.generateUidIdentifier('slot');
+      const scope = path.hub.getScope();
+      if (scope) {
+        scope.push({
+          id: slotId,
+          kind: 'let',
+        });
+      }
+
+      VNodeChild = t.conditionalExpression(
+        t.callExpression(
+          state.get('@vue/babel-plugin-jsx/runtimeIsSlot')(),
+          [t.assignmentExpression('=', slotId, child)],
+        ),
+        slotId,
+        t.objectExpression([
+          t.objectProperty(
+            t.identifier('default'),
+            t.arrowFunctionExpression([], t.arrayExpression(buildIIFE(path, [slotId]))),
+          ),
+          optimize && t.objectProperty(
+            t.identifier('_'),
+            t.numericLiteral(slotFlag),
+          ) as any,
+        ].filter(Boolean)),
+      );
+    } else if (t.isFunctionExpression(child) || t.isArrowFunctionExpression(child)) {
+      VNodeChild = t.objectExpression([
+        t.objectProperty(
+          t.identifier('default'),
+          child,
+        ),
+      ]);
+    } else if (t.isObjectExpression(child)) {
+      VNodeChild = t.objectExpression([
+        ...child.properties,
+        optimize && t.objectProperty(
+          t.identifier('_'),
+          t.numericLiteral(slotFlag),
+        ),
+      ].filter(Boolean as any));
+    } else {
+      VNodeChild = isComponent ? t.objectExpression([
+        t.objectProperty(
+          t.identifier('default'),
+          t.arrowFunctionExpression([], t.arrayExpression([child])),
+        ),
+      ]) : t.arrayExpression([child]);
+    }
+  }
+
+  const createVNode = t.callExpression(createIdentifier(state, 'createVNode'), [
+    tag,
+    props,
+    VNodeChild || t.nullLiteral(),
     !!patchFlag && optimize && t.numericLiteral(patchFlag),
     !!dynamicPropNames.size && optimize
     && t.arrayExpression(

packages/babel-plugin-jsx/test/__snapshots__/snapshot.test.ts.snap

@@ -127,9 +127,53 @@ exports[`override props single: single 1`] = `
 _createVNode(\\"div\\", a, null);"
 `;
 
-exports[`reassign variable as component: reassign variable as component 1`] = `
+exports[`passing object slots via JSX children multiple expressions: multiple expressions 1`] = `
 "import { createVNode as _createVNode } from \\"vue\\";
+import { resolveComponent as _resolveComponent } from \\"vue\\";
+
+_createVNode(_resolveComponent(\\"A\\"), null, {
+  default: () => [foo, bar],
+  _: 1
+});"
+`;
+
+exports[`passing object slots via JSX children single expression, function expression: single expression, function expression 1`] = `
+"import { createVNode as _createVNode } from \\"vue\\";
+import { resolveComponent as _resolveComponent } from \\"vue\\";
+
+_createVNode(_resolveComponent(\\"A\\"), null, {
+  default: () => \\"foo\\"
+});"
+`;
+
+exports[`passing object slots via JSX children single expression, non-literal value: runtime check: single expression, non-literal value: runtime check 1`] = `
+"import { createVNode as _createVNode } from \\"vue\\";
+import { isVNode as _isVNode } from \\"vue\\";
+import { resolveComponent as _resolveComponent } from \\"vue\\";
+
+let _slot;
+
+function _isSlot(s) {
+  return typeof s === 'function' || Object.prototype.toString.call(s) === '[object Object]' && !_isVNode(s);
+}
+
+const foo = () => 1;
+
+_createVNode(_resolveComponent(\\"A\\"), null, _isSlot(_slot = foo()) ? _slot : {
+  default: () => [_slot],
+  _: 1
+});"
+`;
+
+exports[`reassign variable as component: reassign variable as component 1`] = `
+"import { isVNode as _isVNode } from \\"vue\\";
+import { createVNode as _createVNode } from \\"vue\\";
 import { defineComponent } from 'vue';
+
+function _isSlot(s) {
+  return typeof s === 'function' || Object.prototype.toString.call(s) === '[object Object]' && !_isVNode(s);
+}
+
 let a = 1;
 const A = defineComponent({
   setup(_, {
@@ -146,7 +190,7 @@ const _a = function () {
   return a;
 }();
 
-a = _createVNode(A, null, {
+a = _createVNode(A, null, _isSlot(a) ? a : {
   default: () => [_a],
   _: 2
 });"

packages/babel-plugin-jsx/test/index.test.tsx

@@ -1,5 +1,9 @@
 import {
-  reactive, ref, defineComponent, CSSProperties, ComponentPublicInstance,
+  reactive,
+  ref,
+  defineComponent,
+  CSSProperties,
+  ComponentPublicInstance,
 } from 'vue';
 import { shallowMount, mount, VueWrapper } from '@vue/test-utils';
 
@@ -66,9 +70,7 @@ describe('Transform JSX', () => {
 
     const wrapper = mount({
       render() {
-        return (
-          <Child class="parent" foo={1} />
-        );
+        return <Child class="parent" foo={1} />;
       },
     });
     expect(wrapper.classes()).toStrictEqual([]);
@@ -123,7 +125,7 @@ describe('Transform JSX', () => {
     const wrapper = shallowMount({
       setup() {
         // @ts-ignore
-        return () => <div class="a" {...{ class: 'b' } } />;
+        return () => <div class="a" {...{ class: 'b' }} />;
       },
     });
     expect(wrapper.classes().sort()).toEqual(['a', 'b'].sort());
@@ -145,10 +147,12 @@ describe('Transform JSX', () => {
     const wrapper = shallowMount({
       setup() {
         // @ts-ignore
-        return () => <div { ...propsA } { ...propsB } />;
+        return () => <div {...propsA} {...propsB} />;
       },
     });
-    expect(wrapper.html()).toBe('<div style="color: blue; width: 300px; height: 300px;"></div>');
+    expect(wrapper.html()).toBe(
+      '<div style="color: blue; width: 300px; height: 300px;"></div>',
+    );
   });
 
   test('JSXSpreadChild', () => {
@@ -259,7 +263,7 @@ describe('directive', () => {
         calls.push(1);
       },
     };
-    const wrapper = shallowMount(({
+    const wrapper = shallowMount({
       directives: { custom: customDirective },
       setup() {
         return () => (
@@ -272,28 +276,28 @@ describe('directive', () => {
           />
         );
       },
-    }));
+    });
     const node = wrapper.vm.$.subTree;
     expect(calls).toEqual(expect.arrayContaining([1]));
     expect(node.dirs).toHaveLength(1);
   });
 
   test('vHtml', () => {
-    const wrapper = shallowMount(({
+    const wrapper = shallowMount({
       setup() {
         return () => <h1 v-html="<div>foo</div>"></h1>;
       },
-    }));
+    });
     expect(wrapper.html()).toBe('<h1><div>foo</div></h1>');
   });
 
   test('vText', () => {
     const text = 'foo';
-    const wrapper = shallowMount(({
+    const wrapper = shallowMount({
       setup() {
         return () => <div v-text={text}></div>;
       },
-    }));
+    });
     expect(wrapper.html()).toBe('<div>foo</div>');
   });
 });
@@ -315,7 +319,11 @@ describe('slots', () => {
 
     const wrapper = mount({
       setup() {
-        return () => <A v-slots={{ foo: (val: string) => val }}><span>default</span></A>;
+        return () => (
+          <A v-slots={{ foo: (val: string) => val }}>
+            <span>default</span>
+          </A>
+        );
       },
     });
 
@@ -325,11 +333,7 @@ describe('slots', () => {
   test('without default', () => {
     const A = defineComponent({
       setup(_, { slots }) {
-        return () => (
-          <div>
-            {slots.foo?.('foo')}
-          </div>
-        );
+        return () => <div>{slots.foo?.('foo')}</div>;
       },
     });
 
@@ -362,7 +366,11 @@ describe('PatchFlags', () => {
         const onClick = () => {
           visible.value = false;
         };
-        return () => <div v-show={visible.value} onClick={onClick}>NEED_PATCH</div>;
+        return () => (
+          <div v-show={visible.value} onClick={onClick}>
+            NEED_PATCH
+          </div>
+        );
       },
     });
 
@@ -380,7 +388,9 @@ describe('PatchFlags', () => {
         };
 
         return () => (
-          <div {...bindProps} class="static" onClick={onClick}>full props</div>
+          <div {...bindProps} class="static" onClick={onClick}>
+            full props
+          </div>
         );
       },
     });
@@ -455,9 +465,7 @@ describe('variables outside slots', () => {
         const textarea = <textarea id="textarea" {...attrs} />;
         return (
           <A inc={this.inc}>
-            <div>
-              {textarea}
-            </div>
+            <div>{textarea}</div>
             <button id="button" onClick={this.inc}>+1</button>
           </A>
         );
@@ -480,7 +488,6 @@ test('reassign variable as component should work', () => {
   });
 
   /* eslint-disable */
-  // @ts-ignore
   const _a2 = 2;
   a = _a2;
   /* eslint-enable */
@@ -495,3 +502,72 @@ test('reassign variable as component should work', () => {
 
   expect(wrapper.html()).toBe('<span>2</span>');
 });
+
+describe('should support passing object slots via JSX children', () => {
+  const A = defineComponent({
+    setup(_, { slots }) {
+      return () => (
+        <span>
+          {slots.default?.()}
+          {slots.foo?.()}
+        </span>
+      );
+    },
+  });
+
+  test('single expression, variable', () => {
+    const slots = { default: () => 1, foo: () => 2 };
+
+    const wrapper = mount({
+      render() {
+        return <A>{slots}</A>;
+      },
+    });
+
+    expect(wrapper.html()).toBe('<span>12</span>');
+  });
+
+  test('single expression, object literal', () => {
+    const wrapper = mount({
+      render() {
+        return <A>{{ default: () => 1, foo: () => 2 }}</A>;
+      },
+    });
+
+    expect(wrapper.html()).toBe('<span>12</span>');
+  });
+
+  test('single expression, object literal', () => {
+    const wrapper = mount({
+      render() {
+        return <A>{{ default: () => 1, foo: () => 2 }}</A>;
+      },
+    });
+
+    expect(wrapper.html()).toBe('<span>12</span>');
+  });
+
+  test('single expression, non-literal value', () => {
+    const foo = () => 1;
+
+    const wrapper = mount({
+      render() {
+        return <A>{foo()}</A>;
+      },
+    });
+
+    expect(wrapper.html()).toBe('<span>1<!----></span>');
+  });
+
+  test('single expression, function expression', () => {
+    const wrapper = mount({
+      render() {
+        return (
+          <A>{() => 'foo'}</A>
+        );
+      },
+    });
+
+    expect(wrapper.html()).toBe('<span>foo<!----></span>');
+  });
+});

packages/babel-plugin-jsx/test/snapshot.test.ts

@@ -1,6 +1,11 @@
 import { transform } from '@babel/core';
 import JSX, { Opts } from '../src';
 
+interface Test {
+  name: string;
+  from: string;
+}
+
 const transpile = (
   source: string, options: Opts = {},
 ) => new Promise((resolve, reject) => transform(
@@ -18,7 +23,7 @@ const transpile = (
   },
 ));
 
-const tests = [
+const tests: Test[] = [
   {
     name: 'input[type="checkbox"]',
     from: '<input type="checkbox" v-model={test} />',
@@ -155,7 +160,7 @@ tests.forEach((
   );
 });
 
-const overridePropsTests = [{
+const overridePropsTests: Test[] = [{
   name: 'single',
   from: '<div {...a} />',
 }, {
@@ -173,3 +178,34 @@ overridePropsTests.forEach((
     },
   );
 });
+
+const slotsTests: Test[] = [
+  {
+    name: 'multiple expressions',
+    from: '<A>{foo}{bar}</A>',
+  },
+  {
+    name: 'single expression, function expression',
+    from: `
+      <A>{() => "foo"}</A>
+    `,
+  },
+  {
+    name: 'single expression, non-literal value: runtime check',
+    from: `
+      const foo = () => 1;
+      <A>{foo()}</A>;
+    `,
+  },
+];
+
+slotsTests.forEach(({
+  name, from,
+}) => {
+  test(
+    `passing object slots via JSX children ${name}`,
+    async () => {
+      expect(await transpile(from, { optimize: true })).toMatchSnapshot(name);
+    },
+  );
+});