Develop Reference

Vue: Input Manual Autocomplete component

I have a vue-cli project, that has a component named 'AutoCompleteList.vue' that manually handled for searching experience and this component has some buttons that will be fill out the input.
It listens an array as its item list. so when this array has some items, it will be automatically shown; and when I empty this array, it will be automatically hidden.
I defined an oninput event method for my input, that fetches data from server, and fill the array. so the autocomplete list, will not be shown while the user doesn't try to enter something into the input.
I also like to hide the autocomplete list when the user blurs the input (onblur).
but there is a really big problem! when the user chooses one of items (buttons) on the autocomplete list, JS-engine first blurs the input (onblur runs) and then, tries to run onclick method in autocomplete list. but its too late, because the autocomplete list has hidden and there is nothing to do. so the input will not fill out...
here is my code:
src/views/LoginView.vue:
<template>
<InputGroup
label="Your School Name"
inputId="schoolName"
:onInput="schoolNameOnInput"
autoComplete="off"
:onFocus="onFocus"
:onBlur="onBlur"
:vModel="schoolName"
#update:vModel="newValue => schoolName = newValue"
/>
<AutoCompleteList
:items="autoCompleteItems"
:choose="autoCompleteOnChoose"
v-show="autoCompleteItems.length > 0"
:positionY="autoCompletePositionY"
:positionX="autoCompletePositionX"
/>
</template>
<script>
import InputGroup from '../components/InputGroup'
import AutoCompleteList from '../components/AutoCompleteList'
export default {
name: 'LoginView',
components: {
InputGroup,
AutoCompleteList
},
props: [],
data: () => ({
autoCompleteItems: [],
autoCompletePositionY: 0,
autoCompletePositionX: 0,
schoolName: ""
}),
methods: {
async schoolNameOnInput(e) {
const data = await (await fetch(`http://[::1]:8888/schools/${e.target.value}`)).json();
this.autoCompleteItems = data;
},
autoCompleteOnChoose(value, name) {
OO("#schoolName").val(name);
this.schoolName = name;
},
onFocus(e) {
const position = e.target.getBoundingClientRect();
this.autoCompletePositionX = innerWidth - position.right;
this.autoCompletePositionY = position.top + e.target.offsetHeight + 20;
},
onBlur(e) {
// this.autoCompleteItems = [];
// PROBLEM! =================================================================
}
}
}
</script>
src/components/AutoCompleteList.vue:
<template>
<div class="autocomplete-list" :style="'top: ' + this.positionY + 'px; right: ' + this.positionX + 'px;'">
<ul>
<li v-for="(item, index) in items" :key="index">
<button #click="choose(item.value, item.name)" type="button">{{ item.name }}</button>
</li>
</ul>
</div>
</template>
<script>
export default {
name: 'AutoCompleteList',
props: {
items: Array,
positionX: Number,
positionY: Number,
choose: Function
},
data: () => ({
})
}
</script>
src/components/InputGroup.vue:
<template>
<div class="input-group mb-3">
<label class="input-group-text" :for="inputId ?? ''">{{ label }}</label>
<input
:type="type ?? 'text'"
:class="['form-control', ltr && 'ltr']"
:id="inputId ?? ''"
#input="$event => { $emit('update:vModel', $event.target.value); onInput($event); }"
:autocomplete="autoComplete ?? 'off'"
#focus="onFocus"
#blur="onBlur"
:value="vModel"
/>
</div>
</template>
<script>
export default {
name: 'input-group',
props: {
label: String,
ltr: Boolean,
type: String,
inputId: String,
groupingId: String,
onInput: Function,
autoComplete: String,
onFocus: Function,
onBlur: Function,
vModel: String
},
emits: [
'update:vModel'
],
data: () => ({
}),
methods: {
}
}
</script>
Notes on LoginView.vue:
autoCompletePositionX and autoCompletePositionY are used to find the best position to show the autocomplete list; will be changed in onFocus method of the input (inputGroup)
OO("#schoolName").val(name) is used to change the value of the input, works like jQuery (but not exactly)
the [::1]:8888 is my server that used to fetch the search results
If there was any unclear code, ask me in the comment
I need to fix this. any idea?

Thank you, #yoduh
I got the answer.
I knew there should be some differences between when the user focus out the input normally, and when he tries to click on buttons.
the key, was the FocusEvent.relatedTarget property. It should be defined in onblur method. here is its full tutorial.
I defined a property named isFocus and I change it in onBlur method, only when I sure that the focus is not on the dropdown menu, by checking the relatedTarget

text input (input type="text") value is not updating after changing property using an event with LitElement library

The source code:
import { LitElement, html, css } from '../vendor/lit-2.4.0/lit-all.min.js';
export class SearchInput extends LitElement {
static get properties() {
return {
src: { type: String },
items: { type: Array }
}
};
static styles = css`
`;
constructor() {
super();
this.items = [
{ text: 'Hola' },
{ text: 'mundo!' }
];
this.selectedItem = null;
this.text = 'foo';
}
selectItem(item) {
this.selectedItem = item;
this.text = this.selectedItem.text;
}
render() {
return html`
<div class="control">
<input class="input" type="text" value="${this.text}">
<ul class="result-list">
${this.items.map((item) => html`<li #click="${this.selectItem(item)}">${item.text}</li>`)}
</ul>
</div>
`;
}
}
customElements.define('search-input', SearchInput);
The text input (input type="text") value is not updating after changing property (this.text) using an event (this.selectItem) with LitElement library.
I tried it in browser but there is no error in browser console.
I expect that input value update after changing property with the event.

Thanks for the question! There are a few minor issues resulting in the value not updating.
One issue is that this.text is not a reactive property, so changing it isn't scheduling a re-render. Fix is to add text to the static properties.
The second issue is that your event listener click handler is the result of calling this.selectItems(item) and not a function, fixed with: #click=${() => this.selectItems(item)}.
Bonus: You may want to change the value attribute expression to a property expression using the live directive, .value="${live(this.text)}". I suggested this because the native input browser element always updates its contents if you update the value property, but only updates before a user has interacted with it when updating the value attribute. And the live directive is useful to tell Lit to dirty check the live DOM value in the input element.
Your code with the minor fixes: https://lit.dev/playground/#gist=a23dfbcdfbfcfb7de28b1f7255aaa8ee
or running in StackOverflow:
<script type="module">
import { LitElement, html, live } from 'https://cdn.jsdelivr.net/gh/lit/dist#2/all/lit-all.min.js';
class SearchInput extends LitElement {
static get properties() {
return {
src: { type: String },
items: { type: Array },
text: { type: String }, // <- Added this to make `this.text` a reactive property.
}
};
constructor() {
super();
this.items = [
{ text: 'Hola' },
{ text: 'mundo!' },
{ text: 'click these' },
];
this.selectedItem = null;
this.text = 'foo';
}
selectItem(item) {
this.selectedItem = item;
this.text = this.selectedItem.text;
}
render() {
return html`
<div class="control">
<!-- live directive is needed because user can edit the value of the input.
This tells Lit to dirty check against the live DOM value. -->
<input class="input" type="text" .value="${live(this.text)}">
<ul class="result-list">
<!-- Click event is a function -->
${this.items.map((item) =>
html`<li #click="${() => this.selectItem(item)}">${item.text}</li>`)}
</ul>
</div>
`;
}
}
customElements.define('search-input', SearchInput);
</script>
<search-input></search-input>

WYSIWYG Editor not registering update

I am building my own custom WYSIWYG text editor in Angular using a content editable div. I am extracting it as a component. I want to be able to type some text and format it and then when I click a button from the parent component it should either change the text in the editor or update it.
My parent component looks as follows:
#Component({
selector: 'app-parent',
templateUrl: `
<form [formGroup]="form">
<app-default-editor
formControlName="body" >
</app-default-editor>
</form>
<button (click)="changeValue()">Change Value</button>
<p *ngIf="!form.valid">Counter is invalid!</p>
<pre>{{ form.value | json }}</pre>
`
})
export class ParentComponent {
initialText = '<H1>This is the heading</H1>';
form = this.fb.group({
body: '<H1>This is the heading</H1>'
});
changeValue(){
this.form.patchValue({ body: 'This is my new text' });
}
}
My editor component looks as follows:
#Component({
selector: 'app-parent',
templateUrl: `
<button (click)="executeCommand('bold')" ><i class="fas fa-bold"></i></button>
<button (click)="executeCommand('italic')" ><i class="fas fa-italic"></i></button>
<button (click)="executeCommand('underline')" ><i class="fas fa-underline"></i></button>
<div
#htmlEditor
id="htmlEditor"
contenteditable="true"
(input)="onTextChanged()"
[innerHTML]="initialText">
</div>
`
})
export class EditorComponent implements ControlValueAccessor, OnChanges {
#Input()
initialText = "";
#Input()
_textValue = "";
#Input()
minValue = 0;
#ViewChild('htmlEditor') htmlEditor;
ngAfterViewInit() {
this.htmlEditor.nativeElement.innerHTML = this.initialText;
}
get textValue() {
return this._textValue;
}
set textValue(val) {
this._textValue = val;
this.propagateChange(this._textValue);
}
writeValue(value: any) {
if (value !== undefined) {
this.textValue = value;
}
}
propagateChange = (_: any) => { };
registerOnChange(fn) {
this.propagateChange = fn;
}
registerOnTouched() { }
validateFn: Function;
ngOnChanges(changes) {
this.validateFn = createEditorRequiredValidator();
}
onTextChanged() {
this.textValue = this.htmlEditor.nativeElement.innerHTML;
}
executeCommand(cmd) {
document.execCommand(cmd, false, this.htmlEditor.nativeElement);
}
}
export function createEditorRequiredValidator() {
return function validateEditor(c: FormControl) {
let err = {
requiredError: {
given: c.value,
required: true
}
};
return (c.value.length == 0) ? err : null;
}
}
With the current code, I can format text to be bold, italic etc and the form in the parent component can display the value in the tags. When I click the button to change the text to a predefined value the form updates but the editor doesn't show any changes.

There are two little mistakes that prevent your code from working as it should.
1. No provider for NG_VALUE_ACCESSOR
This one should have given you errors in your console. To make sure you can use formControlName directive the component needs to provide a value accessor. You achive that by adding the providers when defining the editor component. Like this:
providers: [
{ provide: NG_VALUE_ACCESSOR, useExisting: forwardRef(() => EditorComponent), multi: true}
]
When you did this the writeValue function within your editor component is called everytime the form control for the field body changes. Lets go to little mistake number two...
2. innerHtml bound to initialText
You update the text property within writeValue but that property is never bound to the template. The innerHtml binding only looks for the initialText property - and that hasn´t changed.
Change your binding to look like this:
<div #htmlEditor
id="htmlEditor"
contenteditable="true"
(input)="onTextChanged()"
[innerHTML]="textValue">
You can utilize the initial text within the getter and return it in case of an empty text value.

I ended up changing the changeValue method in the parent component to:
changeValue(){
this.form.patchValue({ body: [WHATEVER THE TEXT MUST BE] });
this.initialText = [WHATEVER THE TEXT MUST BE]
}
This seems to work but I don't think it is the best answer.

Show hide text box when specific option is selected from dropdown inside dynamic form Angular

I have a form where a user could add one/more div of Address on click of add button.
I want if user select options=5 from the dropdown, want to show and hide textbox in that particular address Div.
Component Code
get contactFormGroup() {
return this.form.get('Array') as FormArray;
}
ngOnInit() {
this.form= this.fb.group({
Array: this.fb.array([])
});
}
createContact(): FormGroup {
return this.fb.group({
ABC: [null, Validators.compose([Validators.required])],
Test: [null, Validators.compose([Validators.required])]
});
}
addContact() {
this.Group.push(this.createContact());
}
showValue(event) {
const selectedValue = event;
if (selectedValue === '5') {
this.showValuetxtbox = true;
} else {
this.showValuetxtbox = false;
}
}

As you are looping to add the divs, you could use a template reference variable on the drop down. e.g #select then refer to that in the *ngIf:
<form [formGroup]="addExpressionform">
<div formArrayName="expressionArray">
<div *ngFor="let item of contactFormGroup.controls; let i = index;" [formGroupName]="i">
<carbon-dropdown #select
(optionSelected)="showValue($event)"
[formControlN]="'UOM'"
[options]="listOptions" [formGroup]="item"
name="UOM"
>
</carbon-dropdown>
<carbon-text-input *ngIf="select.value == 5"
[formControlN]="'Value'"
[formGroup]="item"
name="Value"
>
</carbon-text-input>
<carbon-button type="primary" (click)="submit()" id="save-parameter">Save</carbon-button>
</div>
</div>
</form>
Simplified StackBlitz demo.

Take a look at this Stackblitz, it's referred to in the Angular docs and could serve as boilerplate to what you are trying to achieve.
You should isolate every possible type of question by creating a different class for each one, so you can shape the data and then use ngSwitch to dynamically create the HTML accordingly.
Question base class:
export class QuestionBase<T> {
controlType: string;
value: T;
key: string;
label: string;
// etc
constructor(options) {
// constructor logic
}
}
Some special class that inherents from base class
import { QuestionBase } from './question-base';
export class SpecialQuestion extends QuestionBase<string> {
controlType = 'specialQuestion';
type: string;
// special Question
specialValue: string;
constructor(options) {
super(options);
this.type = options['type'] || '';
}
}
Then, a question component:
<div [formGroup]="form">
<label>{{question.label}}</label>
<div [ngSwitch]="question.controlType">
// controls logic
<input *ngSwitchCase="'textbox'" >
<select *ngSwitchCase="'specialQuestion'"></select>
</div>
</div>
Then you throw this into a container component where you loop through the entire questions array.
This way your code will be future proof and reusable as you add/change functionality to your forms down the road. You won't have to create spaghetti to meet edge case requirements like an extra input field.

Angular Material Autocomplete - How to allow user to add item not in suggested list?

I'm trying to implement the autocomplete component from Angular Material:
https://material.angular.io/components/autocomplete/overview
It works well for letting the user select a particular item from the suggested list but I also want to allow the user to add items not in the list.
So lets say the suggested list has the following items:
Cats
Birds
Dogs
And the user starts typing "Do" and the autocomplete shows "Dogs" as the suggested option (because I'm also filtering the list based on what they type). But then the user continues typing "Dolls" and now nothing is displayed in the autocomplete suggestions. Then the user hits enter and it gets added to the list.
Current behavior is that if what the user typed doesn't exist in the list then they are unable to add the item.

If you add an enter key listener to the input field, you can process the entered value and add it to the options if it doesn't exist. You can also dynamically add whatever the user enters to the list of filtered options as an "add new item" option, or add an "add" icon to the field (e.g. as a matSuffix). Or you can do all three:
Stackblitz
HTML
<form class="example-form">
<mat-form-field class="example-full-width">
<input matInput placeholder="Item" aria-label="Item" [matAutocomplete]="auto" [formControl]="itemCtrl" (keyup.enter)="addOption()">
<mat-autocomplete #auto="matAutocomplete" (optionSelected)="optionSelected($event.option)">
<mat-option *ngFor="let item of filteredItems | async" [value]="item">
<span>{{ item }}</span>
</mat-option>
</mat-autocomplete>
<button *ngIf="showAddButton && itemCtrl.value" matSuffix mat-button mat-icon-button (click)="addOption()"><mat-icon matTooltip='Add "{{itemCtrl.value}}"'>add</mat-icon></button>
</mat-form-field>
</form>
TS
import { Component } from '#angular/core';
import { FormControl } from '#angular/forms';
import { Observable } from 'rxjs/Observable';
import { startWith } from 'rxjs/operators/startWith';
import { map } from 'rxjs/operators/map';
/**
* #title Autocomplete with add new item option
*/
#Component({
selector: 'autocomplete-overview-example',
templateUrl: 'autocomplete-overview-example.html',
styleUrls: ['autocomplete-overview-example.css']
})
export class AutocompleteOverviewExample {
itemCtrl: FormControl;
filteredItems: Observable<any[]>;
showAddButton: boolean = false;
prompt = 'Press <enter> to add "';
items: string[] = [
'Cats',
'Birds',
'Dogs'
];
constructor() {
this.itemCtrl = new FormControl();
this.filteredItems = this.itemCtrl.valueChanges
.pipe(
startWith(''),
map(item => item ? this.filterItems(item) : this.items.slice())
);
}
filterItems(name: string) {
let results = this.items.filter(item =>
item.toLowerCase().indexOf(name.toLowerCase()) === 0);
this.showAddButton = results.length === 0;
if (this.showAddButton) {
results = [this.prompt + name + '"'];
}
return results;
}
optionSelected(option) {
if (option.value.indexOf(this.prompt) === 0) {
this.addOption();
}
}
addOption() {
let option = this.removePromptFromOption(this.itemCtrl.value);
if (!this.items.some(entry => entry === option)) {
const index = this.items.push(option) - 1;
this.itemCtrl.setValue(this.items[index]);
}
}
removePromptFromOption(option) {
if (option.startsWith(this.prompt)) {
option = option.substring(this.prompt.length, option.length -1);
}
return option;
}
}

It's weird that the user can add an item in the suggested list. The list is suggested to the user by someone who knows what to suggest. But anyway...
The user can type anything in the field and ignore the suggestions. By ignoring the suggested Dogs and typing Dolls, user can press an "Add" button which will add whatever is typed in (Dolls) to the options array.
For example, you can do it by listening to the submit event on the form:
(ngSubmit)="options.push(myControl.value); myControl.reset()"
Here's the complete demo as well.