fix(name-binding): add extra props to update one time mode

src/name-expression.js

@@ -1,3 +1,5 @@
+import { bindingMode } from './binding-mode';
+
 function getAU(element) {
   let au = element.au;
 
@@ -43,10 +45,17 @@ export class NameExpression {
 }
 
 class NameBinder {
+  /**
+   * Name binding for reference
+   * @param {Expression} sourceExpression
+   * @param {any} target
+   * @param {any} lookupFunctions
+   */
   constructor(sourceExpression, target, lookupFunctions) {
     this.sourceExpression = sourceExpression;
     this.target = target;
     this.lookupFunctions = lookupFunctions;
+    this.mode = bindingMode.oneTime;
   }
 
   bind(source) {
@@ -64,16 +73,24 @@ class NameBinder {
     this.sourceExpression.assign(this.source, this.target, this.lookupFunctions);
   }
 
+  call() {
+    if (!this.isBound) {
+      return;
+    }
+    this.sourceExpression.assign(this.source, this.target, this.lookupFunctions);
+  }
+
   unbind() {
     if (!this.isBound) {
       return;
     }
     this.isBound = false;
-    if (this.sourceExpression.evaluate(this.source, this.lookupFunctions) === this.target) {
-      this.sourceExpression.assign(this.source, null, this.lookupFunctions);
+    const { source, lookupFunctions, sourceExpression } = this;
+    if (sourceExpression.evaluate(source, lookupFunctions) === this.target) {
+      sourceExpression.assign(source, null, lookupFunctions);
     }
-    if (this.sourceExpression.unbind) {
-      this.sourceExpression.unbind(this, this.source);
+    if (sourceExpression.unbind) {
+      sourceExpression.unbind(this, source);
     }
     this.source = null;
   }

test/name-expression.spec.js

@@ -8,6 +8,7 @@ import {
 } from '../src/ast';
 import {createScopeForTest} from '../src/scope';
 import {NameExpression} from '../src/name-expression';
+import { bindingMode } from '../src/binding-mode';
 
 describe('NameExpression', () => {
   let element;
@@ -23,6 +24,13 @@ describe('NameExpression', () => {
     };
   });
 
+  it('creates one time binding mode binding', () => {
+    let sourceExpression = new AccessScope('foo');
+    let expression = new NameExpression(sourceExpression, 'element');
+    let binding = expression.createBinding(element);
+    expect(binding.mode).toBe(bindingMode.oneTime);
+  });
+
   it('binds element to scope', () => {
     let sourceExpression = new AccessScope('foo');
     let expression = new NameExpression(sourceExpression, 'element');
@@ -104,4 +112,34 @@ describe('NameExpression', () => {
     binding.unbind();
     expect(scope.bindingContext.foo).toBe('should remain');
   });
+
+  it('re-assigns value when invoking call()', () => {
+    let sourceExpression = new AccessScope('foo');
+    let expression = new NameExpression(sourceExpression, 'element');
+    let scope = createScopeForTest({});
+    let binding = expression.createBinding(element);
+    binding.bind(scope);
+    expect(scope.bindingContext.foo).toBe(element);
+    scope.bindingContext.foo = null;
+    expect(binding.target).toBe(element);
+    binding.call();
+    expect(scope.bindingContext.foo).toBe(element);
+  });
+
+  it('does nothing when not bound + invoking call()', () => {
+    let sourceExpression = new AccessScope('foo');
+    let expression = new NameExpression(sourceExpression, 'element');
+    let scope = createScopeForTest({});
+    let binding = expression.createBinding(element);
+    binding.bind(scope);
+    expect(scope.bindingContext.foo).toBe(element);
+    scope.bindingContext.foo = null;
+    expect(binding.target).toBe(element);
+    binding.isBound = false;
+    binding.call();
+    expect(scope.bindingContext.foo).toBe(null);
+    binding.isBound = true;
+    binding.call();
+    expect(scope.bindingContext.foo).toBe(element);
+  });
 });