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Sean Perkins 30b548b167 fix(many): dynamic label support for modern form controls (#27156)
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issue. -->

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etc). Submit multiple pull requests if needed. -->

## What is the current behavior?
<!-- Please describe the current behavior that you are modifying. -->

Developers that are using Ionic v7 are experiencing an issue where
implementations that are intended to use the modern control syntax will
render with the legacy syntax and a warning will be displayed.

The issue is most easily reproduced by not assigning a label to the
control and then asynchronously assigning a label after a duration.

Angular example:
```html
<ion-item>
  <ion-input [label]="label"></ion-input>
</ion-item>
```

```ts
@Component({ ... })
export class MyComponent {
  @Input() label?: string; // initially unset

  ngOnInit() {
    setTimeout(() => this.label = 'Hello world', 500);
  }
}
```

<!-- Issues are required for both bug fixes and features. -->
Issue URL: resolves #27085


## What is the new behavior?
<!-- Please describe the behavior or changes that are being added by
this PR. -->

- Form controls that do not have a decorative label or
`aria-label`/`aria-labelledby` assigned, will default render as modern
controls.
- Legacy form implementations that render an `<ion-label>` within the
item, will continue to render with the legacy template and a warning
will be displayed in the console.
- Modern form syntax supports dynamically set labels

## Does this introduce a breaking change?

- [ ] Yes
- [x] No

<!-- If this introduces a breaking change, please describe the impact
and migration path for existing applications below. -->

Legacy implementations that do not have a decorative label and do not
specify `aria-label` on the control, will be upgraded to the modern
syntax.

For example:
```html
<ion-item>
  <ion-input></ion-input>
</ion-item>
```

Developers that do not want to update to the modern syntax yet should
add the `legacy="true"` attribute to their form control.

## Other information

<!-- Any other information that is important to this PR such as
screenshots of how the component looks before and after the change. -->

Dev-build: `7.0.2-dev.11681157690.1060bc7f`

When migrating the range tests to modern syntax, I observed a visual
clipping issue. This is being addressed in:
https://github.com/ionic-team/ionic-framework/pull/27188. This PR simply
adds the legacy flag so that screenshots are the same as `main`.
2023-04-17 20:30:19 +00:00
..
2023-04-12 09:18:36 -04:00

@ionic/core

Ionic is an open source App Development Framework that makes it easy to build top quality Native and Progressive Web Apps with web technologies.

The Ionic Core package contains the Web Components that make up the reusable UI building blocks of Ionic Framework. These components are designed to be used in traditional frontend view libraries/frameworks (such as Stencil, React, Angular, or Vue), or on their own through traditional JavaScript in the browser.

Features

  • Tiny, highly optimized components built with Stencil
  • Styling for both iOS and Material Design
  • No build or compiling required
  • Simply add the static files to any project
  • Lazy-loaded components without configuration
  • Asynchronous rendering
  • Theming through CSS Variables

How to use

Vanilla HTML

Easiest way to start using Ionic Core is by adding a script tag to the CDN:

<script type="module" src="https://cdn.jsdelivr.net/npm/@ionic/core/dist/ionic/ionic.esm.js"></script>
<script nomodule src="https://cdn.jsdelivr.net/npm/@ionic/core/dist/ionic/ionic.js"></script>
<link href="https://cdn.jsdelivr.net/npm/@ionic/core/css/ionic.bundle.css" rel="stylesheet">

Any Ionic component added to the webpage will automatically load. This includes writing the component tag directly in HTML, or using JavaScript such as document.createElement('ion-toggle').

Additionally, within this package is a dist/ionic.js file and accompanying dist/ionic/ directory. These are the same files which are used by the CDN, and they're available in this package so they can be apart of an app's local development.

Framework Bindings

The @ionic/core package can be used in simple HTML, or by vanilla JavaScript without any framework at all. Ionic also has packages that make it easier to integrate Ionic into a framework's traditional ecosystem and patterns. (However, at the lowest-level framework bindings are still just using Ionic Core and Web Components).

Custom Elements Build (Experimental)

In addition to the default, self lazy-loading components built by Stencil, this package also comes with each component exported as a stand-alone custom element within @ionic/core/components. Each component extends HTMLElement, and does not lazy-load itself. Instead, this package is useful for projects already using a bundler such as Webpack or Rollup. While all components are available to be imported, the custom elements build also ensures bundlers only import what's used, and tree-shakes any unused components.

Below is an example of importing ion-badge, and initializing Ionic so it is able to correctly load the "mode", such as Material Design or iOS. Additionally, the initialize({...}) function can receive the Ionic config.

import { defineCustomElement } from "@ionic/core/components/ion-badge.js";
import { initialize } from "@ionic/core/components";

// Initializes the Ionic config and `mode` behavior
initialize();

//  Defines the `ion-badge` web component
defineCustomElement();

Notice how we import from @ionic/core/components as opposed to @ionic/core. This helps bundlers pull in only the code that is needed.

The defineCustomElement function will automatically define the component as well as any child components that may be required.

For example, if you wanted to use ion-modal, you would do the following:

import { defineCustomElement } from "@ionic/core/components/ion-modal.js";
import { initialize } from "@ionic/core/components";

// Initializes the Ionic config and `mode` behavior
initialize();

//  Defines the `ion-modal` and child `ion-backdrop` web components.
defineCustomElement();

The defineCustomElement function will define ion-modal, but it will also define ion-backdrop, which is a component that ion-modal uses internally.

Using Overlay Controllers

When using an overlay controller, developers will need to define the overlay component before it can be used. Below is an example of using modalController:

import { defineCustomElement } from '@ionic/core/components/ion-modal.js';
import { initialize, modalController } from '@ionic/core/components';

initialize();
defineCustomElement();

const showModal = async () => {
  const modal = await modalController.create({ ... });
  
  ...
}

How to contribute

Check out the CONTRIBUTE guide

License