feat(compiler-core): create transform for v-model (#146)

packages/compiler-core/src/transforms/vModel.ts

@@ -1 +1,54 @@
-// TODO
+import { DirectiveTransform } from '../transform'
+import {
+  createSimpleExpression,
+  createObjectProperty,
+  createCompoundExpression,
+  NodeTypes,
+  Property
+} from '../ast'
+import { createCompilerError, ErrorCodes } from '../errors'
+import { isEmptyExpression } from '../utils'
+
+export const transformModel: DirectiveTransform = (dir, node, context) => {
+  const { exp, arg } = dir
+  if (!exp) {
+    context.onError(createCompilerError(ErrorCodes.X_V_MODEL_NO_EXPRESSION))
+
+    return createTransformProps()
+  }
+
+  if (isEmptyExpression(exp)) {
+    context.onError(
+      createCompilerError(ErrorCodes.X_V_MODEL_MALFORMED_EXPRESSION)
+    )
+
+    return createTransformProps()
+  }
+
+  const propName = arg ? arg : createSimpleExpression('modelValue', true)
+  const eventName = arg
+    ? arg.type === NodeTypes.SIMPLE_EXPRESSION && arg.isStatic
+      ? createSimpleExpression('onUpdate:' + arg.content, true)
+      : createCompoundExpression([
+          createSimpleExpression('onUpdate:', true),
+          '+',
+          ...(arg.type === NodeTypes.SIMPLE_EXPRESSION ? [arg] : arg.children)
+        ])
+    : createSimpleExpression('onUpdate:modelValue', true)
+
+  return createTransformProps([
+    createObjectProperty(propName, dir.exp!),
+    createObjectProperty(
+      eventName,
+      createCompoundExpression([
+        `$event => (`,
+        ...(exp.type === NodeTypes.SIMPLE_EXPRESSION ? [exp] : exp.children),
+        ` = $event)`
+      ])
+    )
+  ])
+}
+
+function createTransformProps(props: Property[] = []) {
+  return { props, needRuntime: false }
+}