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Aurelia function computedFrom
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| <template> | |
| <style> | |
| label {display: block; padding: 4px 0;} | |
| </style> | |
| <hr/> | |
| <label> | |
| First Name: <input value.bind='firstName' /> | |
| </label> | |
| <label> | |
| Last name: <input value.bind='lastName' /> | |
| </label> | |
| <br/> | |
| <div repeat.for='country of countries' style='padding: 5px 0;'> | |
| <button>${showWelcomeMessage($index)}</button> | |
| </div> | |
| <hr/> | |
| </template> |
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| import {computedFrom} from './computed-from'; | |
| export class App { | |
| countries = ['us', 'aus', 'coconut']; | |
| firstName = 'Crab' | |
| lastName = 'Fox' | |
| @computedFrom('firstName', 'lastName') | |
| showWelcomeMessage(index) { | |
| const country = this.countries[index]; | |
| return `${messages[country].hello} to ${this.firstName} ${this.lastName}`; | |
| } | |
| } | |
| const messages = { | |
| us: { | |
| hello: 'Hello ' | |
| }, | |
| aus: { | |
| hello: 'G\'day ' | |
| }, | |
| coconut: { | |
| hello: 'Coconut' | |
| } | |
| } |
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| import { | |
| CallScope | |
| } from 'aurelia-framework'; | |
| /** | |
| * @param {Binding} binding | |
| * @param {Scope} scope | |
| */ | |
| CallScope.prototype.connect = function(binding, scope) { | |
| let context = getContextFor(this.name, scope, this.ancestor); | |
| let func = getFunction(context, this.name, false); | |
| if (func && func.dependencies) { | |
| /**@type {string[] | Expression[]} */ | |
| let dependencies = func.dependencies; | |
| let i = dependencies.length; | |
| while (i--) { | |
| let dependency = dependencies[i]; | |
| if (typeof dependency === 'string') { | |
| dependency = dependencies[i] = binding.observerLocator.parser.parse(dependency); | |
| } | |
| dependency.connect(binding, scope); | |
| } | |
| } | |
| let args = this.args; | |
| let i = args.length; | |
| while (i--) { | |
| args[i].connect(binding, scope); | |
| } | |
| } | |
| function getFunction(obj, name, mustExist) { | |
| let func = obj === null || obj === undefined ? null : obj[name]; | |
| if (typeof func === 'function') { | |
| return func; | |
| } | |
| if (!mustExist && (func === null || func === undefined)) { | |
| return null; | |
| } | |
| throw new Error(`${ name } is not a function`); | |
| } | |
| function getContextFor(name, scope, ancestor) { | |
| let oc = scope.overrideContext; | |
| if (ancestor) { | |
| while (ancestor && oc) { | |
| ancestor--; | |
| oc = oc.parentOverrideContext; | |
| } | |
| if (ancestor || !oc) { | |
| return undefined; | |
| } | |
| return name in oc ? oc : oc.bindingContext; | |
| } | |
| while (oc && !(name in oc) && !(oc.bindingContext && name in oc.bindingContext)) { | |
| oc = oc.parentOverrideContext; | |
| } | |
| if (oc) { | |
| return name in oc ? oc : oc.bindingContext; | |
| } | |
| return scope.bindingContext || scope.overrideContext; | |
| } |
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| import './call-scope'; | |
| export function computedFrom(...rest) { | |
| return deco; | |
| /** | |
| * @param {Function} target | |
| * @param {string} key | |
| * @param {PropertyDescriptor} descriptor | |
| */ | |
| function deco(target, key, descriptor) { | |
| const realTarget = key === undefined ? target : target.constructor; | |
| if (descriptor === undefined | |
| || (descriptor.get === undefined && descriptor.value === undefined) | |
| ) { | |
| throw new Error(`Cannot place 'computedFrom' on property '${key}' for '${realTarget.name}'. No getter or method found. Is it on a normal class field ?`); | |
| } | |
| // decorator on method | |
| if (descriptor.get === undefined) { | |
| descriptor.value.dependencies = rest; | |
| } else { // decorator on getter | |
| descriptor.get.dependencies = rest; | |
| } | |
| return descriptor; | |
| }; | |
| } |
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| <!doctype html> | |
| <html> | |
| <head> | |
| <title>Aurelia</title> | |
| <meta name="viewport" content="width=device-width, initial-scale=1"> | |
| <link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/meyer-reset/2.0/reset.min.css"> | |
| <style> | |
| body { | |
| padding: 20px; | |
| } | |
| .form-component { | |
| display: block; | |
| margin-bottom: 20px; | |
| } | |
| </style> | |
| </head> | |
| <body aurelia-app> | |
| <h1>Loading...</h1> | |
| <script src="https://jdanyow.github.io/rjs-bundle/node_modules/requirejs/require.js"></script> | |
| <script src="https://jdanyow.github.io/rjs-bundle/config.js"></script> | |
| <script src="https://jdanyow.github.io/rjs-bundle/bundles/aurelia.js"></script> | |
| <script src="https://jdanyow.github.io/rjs-bundle/bundles/babel.js"></script> | |
| <script> | |
| require(['aurelia-bootstrapper']); | |
| </script> | |
| </body> | |
| </html> |
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