I cannot get the form to render when passing the JSON string as a variable. If I paste the string into the HTML it works fine. Very confused.
My HTML:
<formio [form]="form" (submit)="onSubmit($event)"></formio>
I preload the JSON and pull from route data. My component:
export class FormIOViewerComponent implements OnInit {
constructor(private route: ActivatedRoute) { }
form:string='';
onSubmit(submission: any) {
console.log(submission);
}
ngOnInit() {
this.form=this.route.snapshot.data.Fields;
console.log(this.form)
}
}
The JSON string prints to console before the error, and again I can copy and paste the JSON string printed from the console into the HTML and it displays fine. The error seen in Chrome:
form-ioviewer.component.html:1 ERROR TypeError: Cannot read property '1' of null
at new Formio (Formio.js:213)
at Form.setForm (Form.js:185)
at new Form (Form.js:106)
at FormioComponent.push../node_modules/angular-formio/FormioBaseComponent.js.FormioBaseComponent.createRenderer (FormioBaseComponent.js:90)
at FormioComponent.push../node_modules/angular-formio/FormioBaseComponent.js.FormioBaseComponent.setForm (FormioBaseComponent.js:111)
at FormioBaseComponent.js:402
at ZoneDelegate.invoke (zone-evergreen.js:359)
at Zone.run (zone-evergreen.js:124)
at NgZone.runOutsideAngular (core.js:39572)
at FormioComponent.push../node_modules/angular-formio/FormioBaseComponent.js.FormioBaseComponent.ngOnChanges (FormioBaseComponent.js:398)
Turns out it won't except a JSON string, it MUST be a object. Something like:
export class formIO {
title:string;
name:string
components: string[]
}
Then pass the object to the form, not the string.
I want to import an element and bind one of its properties. My import fails silently. I expect the value of userLocal to be an object. But, instead, userLocal is undefined.
my-app.html
<link rel="import" href="/src/app-state/state-user-local.html">
...
<state-user-local user-local="{{userLocal}}"></state-user-local>
...
<script>
/* #polymerElement */
class MyApp extends Polymer.Element {
static get is() { return 'my-app; }
static get properties() { return {
userLocal: {
type: Object,
notify: true,
},
...
}}
}
window.customElements.define(MyApp.is, MyApp);
</script>
with the following error message.
The element state-user-local is not defined
I know the import definition is correct because I am using VSCode and when I command+click the import it takes me to the correct file.
I know there is no problem with the <state-user-local> element itself because I successfully import it into other element/s in the app and obtain the expected value of userLocal there.
This problem sounds like what is described at the following links.
The element xxx is not defined (issue #54)
Recognize elements registered with MyElem.is (issue #540)
The first link discusses using "/* #polymerElement */ above the class" which is what I have tried (see above code) without success.
It seems to me that you didn't define the <state-user-local> element inside your file; you defined <my-app>. If you want to use the tag name <state-user-local> you need to define it as such.
<script>
class StateUserLocal extends Polymer.Element {
static get is() { return 'state-user-local'; }
static get properties() { return {
userLocal: {
type: Object,
notify: true,
},
...
}}
}
window.customElements.define(StateUserLocal.is, StateUserLocal);
</script>
I am new to Angular 2 and TypeScript and I'm trying to follow best practices.
Instead of using a simple JavaScript model ({ }), I'm attempting to create a TypeScript class.
However, Angular 2 doesn't seem to like it.
My code is:
import { Component, Input } from "#angular/core";
#Component({
selector: "testWidget",
template: "<div>This is a test and {{model.param1}} is my param.</div>"
})
export class testWidget {
constructor(private model: Model) {}
}
class Model {
param1: string;
}
and I'm using it as:
import { testWidget} from "lib/testWidget";
#Component({
selector: "myComponent",
template: "<testWidget></testWidget>",
directives: [testWidget]
})
I'm getting an error from Angular:
EXCEPTION: Can't resolve all parameters for testWidget: (?).
So I thought, Model isn't defined yet... I'll move it to the top!
Except now I get the exception:
ORIGINAL EXCEPTION: No provider for Model!
How do I accomplish this??
Edit: Thanks to all for the answer. It led me to the right path.
In order to inject this into the constructor, I need to add it to the providers on the component.
This appears to work:
import { Component, Input } from "#angular/core";
class Model {
param1: string;
}
#Component({
selector: "testWidget",
template: "<div>This is a test and {{model.param1}} is my param.</div>",
providers: [Model]
})
export class testWidget {
constructor(private model: Model) {}
}
I'd try this:
Split your Model into a separate file called model.ts:
export class Model {
param1: string;
}
Import it into your component. This will give you the added benefit of being able to use it in other components:
Import { Model } from './model';
Initialize in the component:
export class testWidget {
public model: Model;
constructor(){
this.model = new Model();
this.model.param1 = "your string value here";
}
}
Access it appropriately in the html:
#Component({
selector: "testWidget",
template: "<div>This is a test and {{model.param1}} is my param.</div>"
})
I want to add to the answer a comment made by #PatMigliaccio because it's important to adapt to the latest tools and technologies:
If you are using angular-cli you can call ng g class model and it will generate it for you. model being replaced with whatever naming you desire.
The problem lies that you haven't added Model to either the bootstrap (which will make it a singleton), or to the providers array of your component definition:
#Component({
selector: "testWidget",
template: "<div>This is a test and {{param1}} is my param.</div>",
providers : [
Model
]
})
export class testWidget {
constructor(private model: Model) {}
}
And yes, you should define Model above the Component. But better would be to put it in his own file.
But if you want it to be just a class from which you can create multiple instances, you better just use new.
#Component({
selector: "testWidget",
template: "<div>This is a test and {{param1}} is my param.</div>"
})
export class testWidget {
private model: Model = new Model();
constructor() {}
}
export class Car {
id: number;
make: string;
model: string;
color: string;
year: Date;
constructor(car) {
{
this.id = car.id;
this.make = car.make || '';
this.model = car.model || '';
this.color = car.color || '';
this.year = new Date(car.year).getYear();
}
}
}
The || can become super useful for very complex data objects to default data that doesn't exist.
.
.
In your component.ts or service.ts file you can deserialize response data into the model:
// Import the car model
import { Car } from './car.model.ts';
// If single object
car = new Car(someObject);
// If array of cars
cars = someDataToDeserialize.map(c => new Car(c));
In your case you are having model on same page, but you have it declared after your Component class, so that's you need to use forwardRef to refer to Class. Don't prefer to do this, always have model object in separate file.
export class testWidget {
constructor(#Inject(forwardRef(() => Model)) private service: Model) {}
}
Additionally you have to change you view interpolation to refer to correct object
{{model?.param1}}
Better thing you should do is, you can have your Model Class define in different file & then import it as an when you require it by doing. Also have export before you class name, so that you can import it.
import { Model } from './model';
my code is
import { Component } from '#angular/core';
class model {
username : string;
password : string;
}
#Component({
selector: 'app-root',
templateUrl: './app.component.html',
styleUrls: ['./app.component.css']
})
export class AppComponent {
username : string;
password : string;
usermodel = new model();
login(){
if(this.usermodel.username == "admin"){
alert("hi");
}else{
alert("bye");
this.usermodel.username = "";
}
}
}
and the html goes like this :
<div class="login">
Usernmae : <input type="text" [(ngModel)]="usermodel.username"/>
Password : <input type="text" [(ngModel)]="usermodel.password"/>
<input type="button" value="Click Me" (click)="login()" />
</div>
You can use the angular-cli as the comments in #brendon's answer suggest.
You might also want to try:
ng g class modelsDirectoy/modelName --type=model
/* will create
src/app/modelsDirectoy
├── modelName.model.ts
├── ...
...
*/
Bear in mind:
ng g class !== ng g c
However, you can use ng g cl as shortcut depending on your angular-cli version.
I realize this is a somewhat older question, but I just wanted to point out that you've add the model variable to your test widget class incorrectly. If you need a Model variable, you shouldn't be trying to pass it in through the component constructor. You are only intended to pass services or other types of injectables that way. If you are instantiating your test widget inside of another component and need to pass a model object as, I would recommend using the angular core OnInit and Input/Output design patterns.
As an example, your code should really look something like this:
import { Component, Input, OnInit } from "#angular/core";
import { YourModelLoadingService } from "../yourModuleRootFolderPath/index"
class Model {
param1: string;
}
#Component({
selector: "testWidget",
template: "<div>This is a test and {{model.param1}} is my param.</div>",
providers: [ YourModelLoadingService ]
})
export class testWidget implements OnInit {
#Input() model: Model; //Use this if you want the parent component instantiating this
//one to be able to directly set the model's value
private _model: Model; //Use this if you only want the model to be private within
//the component along with a service to load the model's value
constructor(
private _yourModelLoadingService: YourModelLoadingService //This service should
//usually be provided at the module level, not the component level
) {}
ngOnInit() {
this.load();
}
private load() {
//add some code to make your component read only,
//possibly add a busy spinner on top of your view
//This is to avoid bugs as well as communicate to the user what's
//actually going on
//If using the Input model so the parent scope can set the contents of model,
//add code an event call back for when model gets set via the parent
//On event: now that loading is done, disable read only mode and your spinner
//if you added one
//If using the service to set the contents of model, add code that calls your
//service's functions that return the value of model
//After setting the value of model, disable read only mode and your spinner
//if you added one. Depending on if you leverage Observables, or other methods
//this may also be done in a callback
}
}
A class which is essentially just a struct/model should not be injected, because it means you can only have a single shared instanced of that class within the scope it was provided. In this case, that means a single instance of Model is created by the dependency injector every time testWidget is instantiated. If it were provided at the module level, you would only have a single instance shared among all components and services within that module.
Instead, you should be following standard Object Oriented practices and creating a private model variable as part of the class, and if you need to pass information into that model when you instantiate the instance, that should be handled by a service (injectable) provided by the parent module. This is how both dependency injection and communication is intended to be performed in angular.
Also, as some of the other mentioned, you should be declaring your model classes in a separate file and importing the class.
I would strongly recommend going back to the angular documentation reference and reviewing the basics pages on the various annotations and class types:
https://angular.io/guide/architecture
You should pay particular attention to the sections on Modules, Components and Services/Dependency Injection as these are essential to understanding how to use Angular on an architectural level. Angular is a very architecture heavy language because it is so high level. Separation of concerns, dependency injection factories and javascript versioning for browser comparability are mainly handled for you, but you have to use their application architecture correctly or you'll find things don't work as you expect.
create model.ts in your component directory as below
export module DataModel {
export interface DataObjectName {
propertyName: type;
}
export interface DataObjectAnother {
propertyName: type;
}
}
then in your component import above as,
import {DataModel} from './model';
export class YourComponent {
public DataObject: DataModel.DataObjectName;
}
your DataObject should have all the properties from DataObjectName.
Due to the fact that I am new in meteor/react I can't figure out how to initialize my state variable.
My problem is that I would like to get
my mongo collection through the createContainer from react-meteor-data (as described here),
use the initialized prop to intialize the state variable
But the prop in the constructor is empty. Only when I the "gotClicked" function is called the prop.allLists is filled with the data from mongo.
Does anyone know why? My guess the data is loaded asynchronously, so that the data is not available yet in the constructor.
What would be a better way to get the data?
import React, {Component, PropTypes} from 'react';
import { createContainer } from 'meteor/react-meteor-data';
import {AllLists} from '../api/alllists.js'
export default class MyList extends Component {
constructor(props) {
super();
console.log(props.allLists)
console.log(this.props.allLists)
//allLists is empty
this.state = {
lists: props.allLists
}
}
gotClicked(){
console.log(this.props.allLists)
//allLists is filled
}
render() {
return (
<div className="container" onClick={this.gotClicked.bind(this)}>
</div>
);
}
}
MyList.propTypes = {
allLists: PropTypes.string.isRequired
}
export default createContainer(() => {
return {
allLists: AllLists.find({}).fetch()
};
}, MyList);
You're right, the data is loaded asynchronously, and it might not be available in the constructor. However, the callback function you pass to createContainer is evaluated again when the data is loaded, and it automatically updates the props of your component.
To catch this change, implement the componentWillReceiveProps function in your React component.
componentWillReceiveProps(nextProps) {
this.setState({
lists: nextProps.allLists
});
}
Docs here: https://facebook.github.io/react/docs/component-specs.html
Today, I trying to make my own annotation to use it in Angular2 project.
This annotation must add body class on specific component.
So, I've search on Angular source code, but it's so difficult to see where and how annotation was created.
For the moment, I've tried this :
export function BodyClass(classes: any): ClassDecorator{
classes = classes || {};
if(typeof classes === 'string'){
classes = {classes};
}
return function changeBodyClass(){
console.log('ici');
}
}
And my component :
import {Component} from "angular2/core";
import {RouterOutlet} from "angular2/router";
import {BodyClass} from "../core/annotations/body_class";
#Component({
selector: 'my-component',
template: `
<router-outlet></router-outlet>
`,
})
#BodyClass('test')
export class MyComponent{
}
My console log in the annotation was correctly fired, but I want to use "DOM" class from angular2/src/platform/dom/dom_adapter to add my classes, but DOM in undefined when on console log it (not need to instanciate it).
However, the DOM class works well directly in my component.
I add classes in ngOnInit function, and remove them on ngOnDestroy.
But, I want this behavior on many component, and I think a new annotation is the best way.
Maybe you have a better idea for this ? Or to work with DOM class on a annotation ?
Thanks !
It's not so obvious since you want to work at the component instance level and not at the component class one. So you need to wrap the corresponding constructor function.
export function MyComponentDecorator(value: string) {
return function (target: Function) {
var original = target;
function construct(constructor, args) {
var c : any = function () {
// Call the target constructor
var ret = constructor.apply(this, args);
// Add your additional processing
return ret;
}
c.prototype = constructor.prototype;
return new c();
}
// The new constructor
// Don't forget to add a name at this function
// since Angular requires it for the template compilation
var f : any = function WrappedComponent(...args) {
return construct(original, args);
}
f.prototype = original.prototype;
return f;
}
}
At this point, you wrap the component instance but you lose the component metadata. You need to copy them by hand:
f.prototype = original.prototype;
var annotations = Reflect.getMetadata('annotations', original));
Reflect.defineMetadata('annotations', annotations, f);
var properties = Reflect.getMetadata('propMetadata', original));
Reflect.defineMetadata('propMetadata', properties, f);
return f;
To use this decorator simply add it before or after the #Component one:
#MyComponentDecorator()
#Component({
selector: 'sub',
template: `
<div (click)="showMessage()">Test</div>
`
})
export class SubComponent {
(...)
}
You can notice that this decorator only copies the metadata at the component level and not the other ones like properties (with #Input)...
See this plunkr: https://plnkr.co/edit/PrAvliIpWTNFAtH33bHA?p=preview.