feat(spread-assign): Add implementation

src/convert-spread-assign.ts

@@ -0,0 +1,47 @@
+import { namedTypes } from 'ast-types';
+import { API, FileInfo, Options } from 'jscodeshift';
+
+type ObjectProperties =
+  | namedTypes.SpreadElement
+  | namedTypes.ObjectProperty
+  | namedTypes.Property
+  | namedTypes.ObjectMethod
+  | namedTypes.SpreadProperty;
+
+export default function transform(file: FileInfo, api: API, options: Options): string {
+  const j = api.jscodeshift;
+
+  return j(file.source)
+    .find(j.ObjectExpression)
+    .filter((path) => path.value.properties.some(({ type }) => type === 'SpreadElement'))
+    .forEach((path) => {
+      // create array of
+      const { properties } = path.value;
+      let queue: ObjectProperties[] = [];
+      const objectAssign = j.callExpression(j.memberExpression(j.identifier('Object'), j.identifier('assign')), [
+        j.objectExpression([]),
+      ]);
+      for (const property of properties) {
+        if (property.type === 'SpreadElement') {
+          if (queue.length > 0) {
+            const objectExpression = j.objectExpression(queue);
+            objectAssign.arguments.push(objectExpression);
+          }
+          if (property.argument.type === 'Identifier') {
+            objectAssign.arguments.push(j.identifier(property.argument.name));
+          } else if (property.argument.type === 'ObjectExpression') {
+            objectAssign.arguments.push(j.objectExpression(property.argument.properties));
+          }
+          queue = [];
+        } else {
+          queue.push(property);
+        }
+      }
+      if (queue.length > 0) {
+        const objectExpression = j.objectExpression(queue);
+        objectAssign.arguments.push(objectExpression);
+      }
+      j(path).replaceWith(objectAssign);
+    })
+    .toSource(options);
+}

src/index.ts

@@ -10,6 +10,10 @@ const TRANSFORMS = [
     value: 'remove-debugger',
   },
   // YARN PLOP TRANSFORMS
+  {
+    name: 'Convert object spread patterns to Object.assign()',
+    value: 'convert-spread-assign',
+  },
   {
     name: 'Convert then() promises to async / await',
     value: 'convert-then-async',