66 lines
2.2 KiB
Markdown
66 lines
2.2 KiB
Markdown
# How To >> Extend a native Input ||20
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```js script
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import { html } from '@mdjs/mdjs-preview';
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import { LionInput } from '@lion/input';
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import { LionInputDate } from '@lion/input-date';
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import { loadDefaultFeedbackMessages } from '@lion/validate-messages';
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import '@lion/input/define';
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import '../../fundamentals/systems/form/assets/h-output.js';
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loadDefaultFeedbackMessages();
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```
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Input fields can be created by extending [LionInput](../../components/input/overview.md).
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> In case you want to wrap a custom form element, follow [Create a custom Field](./create-a-custom-field.md).
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For this tutorial, we create an input that wraps native `input[type=datetime-local]`.
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This is as simple as adding a type:
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```js preview-story
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export const extendLionInput = () => {
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class LionInputDatetime extends LionInput {
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constructor() {
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super();
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this.type = 'datetime-local';
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}
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}
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customElements.define('lion-input-datetime', LionInputDatetime);
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return html`<lion-input-datetime label="With Date string"></lion-input-datetime>
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<h-output .show="${['modelValue', 'touched', 'dirty', 'focused']}"></h-output>`;
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};
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```
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However, we might want to have a more advanced modelValue. In the example above, our modelValue is
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a serialized datetime string.
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If we want our modelValue to be of type Date, we should do the following:
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```js preview-story
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export const extendLionInputDate = () => {
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function toIsoDatetime(d) {
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return d && new Date(d.getTime() - d.getTimezoneOffset() * 60000).toISOString().split('.')[0];
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}
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function fromIsoDatetime(value) {
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return new Date(value);
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}
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class LionInputDatetimeWithObject extends LionInputDate {
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constructor() {
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super();
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this.type = 'datetime-local';
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this.parser = fromIsoDatetime;
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this.deserializer = fromIsoDatetime;
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this.serializer = toIsoDatetime;
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this.formatter = toIsoDatetime;
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}
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}
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customElements.define('lion-input-datetime-with-object', LionInputDatetimeWithObject);
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return html`<lion-input-datetime-with-object
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label="With Date object"
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></lion-input-datetime-with-object>
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<h-output .show="${['modelValue', 'touched', 'dirty', 'focused']}"></h-output>`;
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};
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```
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