Use helper-builder-react-jsx inside plugin-transform-react-inline-elements (#6294)

* Use helper-builder-react-jsx inside plugin-transform-react-inline-elements.

This avoids duplicating the logic for converting jsx elements to plain JavaScript.

* Add a comment which explains the _jsx signature, [skip ci]
so it is a little bit easier to understand what all those .splice() calls do

packages/babel-helper-builder-react-jsx/README.md

@@ -13,6 +13,10 @@ type ElementState = {
 };
 
 require("babel-helper-builder-react-jsx")({
+  filter: function (element: JSXElement) {
+    // if returns false, the element isn't transformed
+  },
+
   pre: function (state: ElementState) {
     // called before building the element
   },

packages/babel-helper-builder-react-jsx/src/index.js

@@ -21,10 +21,10 @@ export default function(opts) {
 
   visitor.JSXElement = {
     exit(path, file) {
-      const callExpr = buildElementCall(path.get("openingElement"), file);
-
-      callExpr.arguments = callExpr.arguments.concat(path.node.children);
-      path.replaceWith(t.inherits(callExpr, path.node));
+      const callExpr = buildElementCall(path, file);
+      if (callExpr) {
+        path.replaceWith(t.inherits(callExpr, path.node));
+      }
     },
   };
 
@@ -79,9 +79,15 @@ export default function(opts) {
   }
 
   function buildElementCall(path, file) {
-    path.parent.children = t.react.buildChildren(path.parent);
+    if (opts.filter && !opts.filter(path.node, file)) return;
 
-    const tagExpr = convertJSXIdentifier(path.node.name, path.node);
+    const openingPath = path.get("openingElement");
+    openingPath.parent.children = t.react.buildChildren(openingPath.parent);
+
+    const tagExpr = convertJSXIdentifier(
+      openingPath.node.name,
+      openingPath.node,
+    );
     const args = [];
 
     let tagName;
@@ -101,14 +107,14 @@ export default function(opts) {
       opts.pre(state, file);
     }
 
-    let attribs = path.node.attributes;
+    let attribs = openingPath.node.attributes;
     if (attribs.length) {
       attribs = buildOpeningElementAttributes(attribs, file);
     } else {
       attribs = t.nullLiteral();
     }
 
-    args.push(attribs);
+    args.push(attribs, ...path.node.children);
 
     if (opts.post) {
       opts.post(state, file);

packages/babel-plugin-transform-react-inline-elements/package.json

@@ -8,6 +8,9 @@
   "keywords": [
     "babel-plugin"
   ],
+  "dependencies": {
+    "babel-helper-builder-react-jsx": "7.0.0-beta.1"
+  },
   "devDependencies": {
     "babel-helper-plugin-test-runner": "7.0.0-beta.1"
   }

packages/babel-plugin-transform-react-inline-elements/src/index.js

@@ -1,3 +1,5 @@
+import helper from "babel-helper-builder-react-jsx";
+
 export default function({ types: t }) {
   function hasRefOrSpread(attrs) {
     for (let i = 0; i < attrs.length; i++) {
@@ -14,60 +16,45 @@ export default function({ types: t }) {
     );
   }
 
-  function getAttributeValue(attr) {
-    let value = attr.value;
-    if (!value) return t.booleanLiteral(true);
-    if (t.isJSXExpressionContainer(value)) value = value.expression;
-    return value;
-  }
-
-  return {
-    visitor: {
-      JSXElement(path, file) {
-        const { node } = path;
-
-        // filter
-        const open = node.openingElement;
-        if (hasRefOrSpread(open.attributes)) return;
-
-        // init
-        const props = t.objectExpression([]);
-        let key = null;
-        let type = open.name;
-
-        if (t.isJSXIdentifier(type) && t.react.isCompatTag(type.name)) {
-          type = t.stringLiteral(type.name);
-        }
-
-        function pushProp(objProps, key, value) {
-          objProps.push(t.objectProperty(key, value));
-        }
-
-        // props
-        for (const attr of (open.attributes: Array<Object>)) {
-          if (isJSXAttributeOfName(attr, "key")) {
-            key = getAttributeValue(attr);
-          } else {
-            const name = attr.name.name;
-            const propertyKey = t.isValidIdentifier(name)
-              ? t.identifier(name)
-              : t.stringLiteral(name);
-            pushProp(props.properties, propertyKey, getAttributeValue(attr));
-          }
-        }
-
-        const args = [type, props];
-        if (key || node.children.length) {
-          const children = t.react.buildChildren(node);
-          args.push(
-            key || t.unaryExpression("void", t.numericLiteral(0), true),
-            ...children,
-          );
-        }
-
-        const el = t.callExpression(file.addHelper("jsx"), args);
-        path.replaceWith(el);
-      },
+  const visitor = helper({
+    filter(node) {
+      return !hasRefOrSpread(node.openingElement.attributes);
     },
-  };
+    pre(state) {
+      const tagName = state.tagName;
+      const args = state.args;
+      if (t.react.isCompatTag(tagName)) {
+        args.push(t.stringLiteral(tagName));
+      } else {
+        args.push(state.tagExpr);
+      }
+    },
+    post(state, pass) {
+      state.callee = pass.addHelper("jsx");
+      // NOTE: The arguments passed to the "jsx" helper are:
+      //   (element, props, key, ...children) or (element, props)
+      // The argument generated by the helper are:
+      //   (element, { ...props, key }, ...children)
+
+      const props = state.args[1];
+      let hasKey = false;
+      if (t.isObjectExpression(props)) {
+        const keyIndex = props.properties.findIndex(prop =>
+          t.isIdentifier(prop.key, { name: "key" }),
+        );
+        if (keyIndex > -1) {
+          state.args.splice(2, 0, props.properties[keyIndex].value);
+          props.properties.splice(keyIndex, 1);
+          hasKey = true;
+        }
+      } else if (t.isNullLiteral(props)) {
+        state.args.splice(1, 1, t.objectExpression([]));
+      }
+
+      if (!hasKey && state.args.length > 2) {
+        state.args.splice(2, 0, t.unaryExpression("void", t.numericLiteral(0)));
+      }
+    },
+  });
+  return { visitor };
 }

packages/babel-plugin-transform-react-inline-elements/test/fixtures/inline-elements/multiline/expected.js

@@ -1 +1 @@
-babelHelpers.jsx(Baz, {}, void 0);
+babelHelpers.jsx(Baz, {});

packages/babel-plugin-transform-react-inline-elements/test/fixtures/regressions/6276/actual.js

@@ -0,0 +1,3 @@
+var test = <T default="
+    some string
+  " />;

packages/babel-plugin-transform-react-inline-elements/test/fixtures/regressions/6276/expected.js

@@ -0,0 +1,3 @@
+var test = babelHelpers.jsx(T, {
+  "default": " some string "
+});