[FIX] portal: do not crash in dev mode

Before this commit, the props validation would fail in dev mode because
it did not expect a slot prop.

src/portal.ts

@@ -57,6 +57,7 @@ export class Portal extends Component {
     target: {
       type: String,
     },
+    slots: true,
   };
 
   constructor(props: any, env: any, node: ComponentNode) {

tests/misc/__snapshots__/portal.test.ts.snap

@@ -67,6 +67,27 @@ exports[`Portal basic use of portal 1`] = `
 }"
 `;
 
+exports[`Portal basic use of portal in dev mode 1`] = `
+"function anonymous(bdom, helpers
+) {
+  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  
+  let block1 = createBlock(\`<div><span>1</span><block-child-0/></div>\`);
+  let block2 = createBlock(\`<p>2</p>\`);
+  
+  function slot1(ctx, node, key = \\"\\") {
+    return block2();
+  }
+  
+  return function template(ctx, node, key = \\"\\") {
+    const props2 = {target: '#outside',slots: {'default': {__render: slot1, __ctx: ctx}}}
+    helpers.validateProps(\`Portal\`, props2, ctx)
+    let b3 = component(\`Portal\`, props2, key + \`__3\`, node, ctx);
+    return block1([], [b3]);
+  }
+}"
+`;
+
 exports[`Portal conditional use of Portal (with sub Component) 1`] = `
 "function anonymous(bdom, helpers
 ) {

tests/misc/portal.test.ts

@@ -10,10 +10,12 @@ import {
 } from "../../src";
 import { Portal, xml } from "../../src/";
 import { elem, makeTestFixture, nextTick, snapshotEverything } from "../helpers";
+import { DEV_MSG } from "../../src/app/app";
 
 let fixture: HTMLElement;
 let originalconsoleWarn = console.warn;
 let mockConsoleWarn: any;
+const info = console.info;
 
 function addOutsideDiv(fixture: HTMLElement): HTMLElement {
   let outside = document.createElement("div");
@@ -24,6 +26,19 @@ function addOutsideDiv(fixture: HTMLElement): HTMLElement {
 
 snapshotEverything();
 
+beforeAll(() => {
+  console.info = (message: any) => {
+    if (message === DEV_MSG) {
+      return;
+    }
+    info(message);
+  };
+});
+
+afterAll(() => {
+  console.info = info;
+});
+
 beforeEach(() => {
   fixture = makeTestFixture();
   mockConsoleWarn = jest.fn(() => {});
@@ -53,6 +68,24 @@ describe("Portal", () => {
     expect(fixture.innerHTML).toBe('<div id="outside"><p>2</p></div><div><span>1</span></div>');
   });
 
+  test("basic use of portal in dev mode", async () => {
+    class Parent extends Component {
+      static components = { Portal };
+      static template = xml`
+          <div>
+            <span>1</span>
+            <Portal target="'#outside'">
+              <p>2</p>
+            </Portal>
+          </div>`;
+    }
+
+    addOutsideDiv(fixture);
+    await mount(Parent, fixture, { dev: true });
+
+    expect(fixture.innerHTML).toBe('<div id="outside"><p>2</p></div><div><span>1</span></div>');
+  });
+
   test("conditional use of Portal", async () => {
     class Parent extends Component {
       static components = { Portal };