[IMP] component: add .bind suffix to props for easy binding

src/app/template_helpers.ts

@@ -124,6 +124,23 @@ export function safeOutput(value: any): ReturnType<typeof toggler> {
   return toggler(safeKey, block);
 }
 
+let boundFunctions = new WeakMap();
+
+function bind(ctx: any, fn: Function): Function {
+  let component = ctx.__owl__.component;
+  let boundFnMap = boundFunctions.get(component);
+  if (!boundFnMap) {
+    boundFnMap = new WeakMap();
+    boundFunctions.set(component, boundFnMap);
+  }
+  let boundFn = boundFnMap.get(fn);
+  if (!boundFn) {
+    boundFn = fn.bind(component);
+    boundFnMap.set(fn, boundFn);
+  }
+  return boundFn;
+}
+
 export const UTILS = {
   withDefault,
   zero: Symbol("zero"),
@@ -137,4 +154,5 @@ export const UTILS = {
   toNumber,
   validateProps,
   safeOutput,
+  bind,
 };

src/compiler/code_generator.ts

@@ -975,10 +975,19 @@ export class CodeGenerator {
     // props
     const props: string[] = [];
     let hasSlotsProp = false;
-    for (let p in ast.props) {
-      const propName = /^[a-z_]+$/i.test(p) ? p : `'${p}'`;
-      props.push(`${propName}: ${this.captureExpression(ast.props[p]) || undefined}`);
-      if (p === "slots") {
+    for (let propName in ast.props) {
+      let propValue = this.captureExpression(ast.props[propName]) || undefined;
+      if (propName.includes(".")) {
+        let [name, suffix] = propName.split(".");
+        if (suffix === "bind") {
+          this.helpers.add("bind");
+          propName = name;
+          propValue = `bind(ctx, ${propValue})`;
+        }
+      }
+      propName = /^[a-z_]+$/i.test(propName) ? propName : `'${propName}'`;
+      props.push(`${propName}: ${propValue}`);
+      if (propName === "slots") {
         hasSlotsProp = true;
       }
     }

tests/components/__snapshots__/props.test.ts.snap

@@ -262,3 +262,49 @@ exports[`basics template string in prop 2`] = `
   }
 }"
 `;
+
+exports[`bound functions is referentially equal after update 1`] = `
+"function anonymous(bdom, helpers
+) {
+  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  
+  return function template(ctx, node, key = \\"\\") {
+    return text(ctx['props'].val);
+  }
+}"
+`;
+
+exports[`bound functions is referentially equal after update 2`] = `
+"function anonymous(bdom, helpers
+) {
+  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { bind } = helpers;
+  
+  return function template(ctx, node, key = \\"\\") {
+    return component(\`Child\`, {val: ctx['state'].val,fn: bind(ctx, ctx['someFunction'])}, key + \`__1\`, node, ctx);
+  }
+}"
+`;
+
+exports[`can bind function prop with bind suffix 1`] = `
+"function anonymous(bdom, helpers
+) {
+  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  
+  return function template(ctx, node, key = \\"\\") {
+    return text(\`child\`);
+  }
+}"
+`;
+
+exports[`can bind function prop with bind suffix 2`] = `
+"function anonymous(bdom, helpers
+) {
+  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { bind } = helpers;
+  
+  return function template(ctx, node, key = \\"\\") {
+    return component(\`Child\`, {doSomething: bind(ctx, ctx['doSomething'])}, key + \`__1\`, node, ctx);
+  }
+}"
+`;

tests/components/props.test.ts

@@ -1,6 +1,6 @@
-import { Component, mount, useState } from "../../src";
+import { Component, mount, onWillUpdateProps, useState } from "../../src";
 import { xml } from "../../src/tags";
-import { makeTestFixture, snapshotEverything } from "../helpers";
+import { makeTestFixture, nextTick, snapshotEverything } from "../helpers";
 
 let fixture: HTMLElement;
 
@@ -176,3 +176,53 @@ describe("basics", () => {
     await mount(Parent, fixture);
   });
 });
+
+test("can bind function prop with bind suffix", async () => {
+  class Child extends Component {
+    static template = xml`child`;
+    setup() {
+      this.props.doSomething(123);
+    }
+  }
+
+  let boundedThing: any = null;
+
+  class Parent extends Component {
+    static template = xml`<Child doSomething.bind="doSomething"/>`;
+    static components = { Child };
+
+    doSomething(val: number) {
+      expect(val).toBe(123);
+      boundedThing = this;
+    }
+  }
+
+  const parent = await mount(Parent, fixture);
+  expect(boundedThing).toBe(parent);
+  expect(fixture.innerHTML).toBe("child");
+});
+
+test("bound functions is referentially equal after update", async () => {
+  let isEqual = false;
+  class Child extends Component {
+    static template = xml`<t t-esc="props.val"/>`;
+    setup() {
+      onWillUpdateProps((nextProps: any) => {
+        isEqual = nextProps.fn === this.props.fn;
+      });
+    }
+  }
+
+  class Parent extends Component {
+    static template = xml`<Child val="state.val" fn.bind="someFunction"/>`;
+    static components = { Child };
+    state = useState({ val: 1 });
+    someFunction() {}
+  }
+
+  const parent = await mount(Parent, fixture);
+  parent.state.val = 3;
+  await nextTick();
+  expect(fixture.innerHTML).toBe("3");
+  expect(isEqual).toBe(true);
+});