lion/packages/field/src/FormControlMixin.js

527 lines
17 KiB
JavaScript

import { html, css, nothing, dedupeMixin, SlotMixin } from '@lion/core';
import { FormRegisteringMixin } from './FormRegisteringMixin.js';
import { getAriaElementsInRightDomOrder } from './utils/getAriaElementsInRightDomOrder.js';
/**
* Generates random unique identifier (for dom elements)
* @param {string} prefix
*/
function uuid(prefix) {
return `${prefix}-${Math.random()
.toString(36)
.substr(2, 10)}`;
}
/**
* #FormControlMixin :
*
* This Mixin is a shared fundament for all form components, it's applied on:
* - LionField (which is extended to LionInput, LionTextarea, LionSelect etc. etc.)
* - LionFieldset (which is extended to LionRadioGroup, LionCheckboxGroup, LionForm)
*
* @polymerMixin
* @mixinFunction
*/
export const FormControlMixin = dedupeMixin(
superclass =>
// eslint-disable-next-line no-shadow, no-unused-vars
class FormControlMixin extends FormRegisteringMixin(SlotMixin(superclass)) {
static get properties() {
return {
/**
* When no light dom defined and prop set
*/
label: String,
/**
* When no light dom defined and prop set
*/
helpText: {
type: String,
attribute: 'help-text',
},
/**
* Contains all elements that should end up in aria-labelledby of `._inputNode`
*/
_ariaLabelledNodes: Array,
/**
* Contains all elements that should end up in aria-describedby of `._inputNode`
*/
_ariaDescribedNodes: Array,
};
}
get slots() {
return {
...super.slots,
label: () => {
const label = document.createElement('label');
label.textContent = this.label;
return label;
},
'help-text': () => {
const helpText = document.createElement('div');
helpText.textContent = this.helpText;
return helpText;
},
};
}
updated(changedProps) {
super.updated(changedProps);
if (changedProps.has('_ariaLabelledNodes')) {
this.__reflectAriaAttr(
'aria-labelledby',
this._ariaLabelledNodes,
this.__reorderAriaLabelledNodes,
);
}
if (changedProps.has('_ariaDescribedNodes')) {
this.__reflectAriaAttr(
'aria-describedby',
this._ariaDescribedNodes,
this.__reorderAriaDescribedNodes,
);
}
if (changedProps.has('label')) {
this._onLabelChanged({ label: this.label });
}
if (changedProps.has('helpText')) {
this._onHelpTextChanged({ helpText: this.helpText });
}
}
get _inputNode() {
return this.__getDirectSlotChild('input');
}
get _labelNode() {
return this.__getDirectSlotChild('label');
}
get _helpTextNode() {
return this.__getDirectSlotChild('help-text');
}
get _feedbackNode() {
return this.__getDirectSlotChild('feedback');
}
constructor() {
super();
this._inputId = uuid(this.localName);
this._ariaLabelledNodes = [];
this._ariaDescribedNodes = [];
}
connectedCallback() {
super.connectedCallback();
this._enhanceLightDomClasses();
this._enhanceLightDomA11y();
}
/**
* Public methods
*/
_enhanceLightDomClasses() {
if (this._inputNode) {
this._inputNode.classList.add('form-control');
}
}
_enhanceLightDomA11y() {
const { _inputNode, _labelNode, _helpTextNode, _feedbackNode } = this;
if (_inputNode) {
_inputNode.id = _inputNode.id || this._inputId;
}
if (_labelNode) {
_labelNode.setAttribute('for', this._inputId);
this.addToAriaLabelledBy(_labelNode, { idPrefix: 'label' });
}
if (_helpTextNode) {
this.addToAriaDescribedBy(_helpTextNode, { idPrefix: 'help-text' });
}
if (_feedbackNode) {
_feedbackNode.setAttribute('aria-live', 'polite');
this.addToAriaDescribedBy(_feedbackNode, { idPrefix: 'feedback' });
}
this._enhanceLightDomA11yForAdditionalSlots();
}
/**
* Enhances additional slots(prefix, suffix, before, after) defined by developer.
*
* When boolean attribute data-label or data-description is found,
* the slot element will be connected to the input via aria-labelledby or aria-describedby
*/
_enhanceLightDomA11yForAdditionalSlots(
additionalSlots = ['prefix', 'suffix', 'before', 'after'],
) {
additionalSlots.forEach(additionalSlot => {
const element = this.__getDirectSlotChild(additionalSlot);
if (element) {
if (element.hasAttribute('data-label') === true) {
this.addToAriaLabelledBy(element, { idPrefix: additionalSlot });
}
if (element.hasAttribute('data-description') === true) {
this.addToAriaDescribedBy(element, { idPrefix: additionalSlot });
}
}
});
}
/**
* Will handle help text, validation feedback and character counter,
* prefix/suffix/before/after (if they contain data-description flag attr).
* Also, contents of id references that will be put in the <lion-field>._ariaDescribedby property
* from an external context, will be read by a screen reader.
*/
__reflectAriaAttr(attrName, nodes, reorder) {
if (this._inputNode) {
if (reorder) {
const insideNodes = nodes.filter(n => this.contains(n));
const outsideNodes = nodes.filter(n => !this.contains(n));
// eslint-disable-next-line no-param-reassign
nodes = [...getAriaElementsInRightDomOrder(insideNodes), ...outsideNodes];
}
const string = nodes.map(n => n.id).join(' ');
this._inputNode.setAttribute(attrName, string);
}
}
_onLabelChanged({ label }) {
if (this._labelNode) {
this._labelNode.textContent = label;
}
}
_onHelpTextChanged({ helpText }) {
if (this._helpTextNode) {
this._helpTextNode.textContent = helpText;
}
}
/**
* Default Render Result:
* <div class="form-field__group-one">
* <div class="form-field__label">
* <slot name="label"></slot>
* </div>
* <small class="form-field__help-text">
* <slot name="help-text"></slot>
* </small>
* </div>
* <div class="form-field__group-two">
* <div class="input-group">
* <div class="input-group__before">
* <slot name="before"></slot>
* </div>
* <div class="input-group__container">
* <div class="input-group__prefix">
* <slot name="prefix"></slot>
* </div>
* <div class="input-group__input">
* <slot name="input"></slot>
* </div>
* <div class="input-group__suffix">
* <slot name="suffix"></slot>
* </div>
* </div>
* <div class="input-group__after">
* <slot name="after"></slot>
* </div>
* </div>
* <div class="form-field__feedback">
* <slot name="feedback"></slot>
* </div>
* </div>
*/
render() {
return html`
<div class="form-field__group-one">
${this.groupOneTemplate()}
</div>
<div class="form-field__group-two">
${this.groupTwoTemplate()}
</div>
`;
}
groupOneTemplate() {
return html`
${this.labelTemplate()} ${this.helpTextTemplate()}
`;
}
groupTwoTemplate() {
return html`
${this.inputGroupTemplate()} ${this.feedbackTemplate()}
`;
}
// eslint-disable-next-line class-methods-use-this
labelTemplate() {
return html`
<div class="form-field__label">
<slot name="label"></slot>
</div>
`;
}
// eslint-disable-next-line class-methods-use-this
helpTextTemplate() {
return html`
<small class="form-field__help-text">
<slot name="help-text"></slot>
</small>
`;
}
inputGroupTemplate() {
return html`
<div class="input-group">
${this.inputGroupBeforeTemplate()}
<div class="input-group__container">
${this.inputGroupPrefixTemplate()} ${this.inputGroupInputTemplate()}
${this.inputGroupSuffixTemplate()}
</div>
${this.inputGroupAfterTemplate()}
</div>
`;
}
// eslint-disable-next-line class-methods-use-this
inputGroupBeforeTemplate() {
return html`
<div class="input-group__before">
<slot name="before"></slot>
</div>
`;
}
inputGroupPrefixTemplate() {
return !Array.from(this.children).find(child => child.slot === 'prefix')
? nothing
: html`
<div class="input-group__prefix">
<slot name="prefix"></slot>
</div>
`;
}
// eslint-disable-next-line class-methods-use-this
inputGroupInputTemplate() {
return html`
<div class="input-group__input">
<slot name="input"></slot>
</div>
`;
}
inputGroupSuffixTemplate() {
return !Array.from(this.children).find(child => child.slot === 'suffix')
? nothing
: html`
<div class="input-group__suffix">
<slot name="suffix"></slot>
</div>
`;
}
// eslint-disable-next-line class-methods-use-this
inputGroupAfterTemplate() {
return html`
<div class="input-group__after">
<slot name="after"></slot>
</div>
`;
}
// eslint-disable-next-line class-methods-use-this
feedbackTemplate() {
return html`
<div class="form-field__feedback">
<slot name="feedback"></slot>
</div>
`;
}
/**
* All CSS below is written from a generic mindset, following BEM conventions:
* https://en.bem.info/methodology/
* Although the CSS and HTML are implemented by the component, they should be regarded as
* totally decoupled.
*
* Not only does this force us to write better structured css, it also allows for future
* reusability in many different ways like:
* - disabling shadow DOM for a component (for water proof encapsulation can be combined with
* a build step)
* - easier translation to more flexible, WebComponents agnostic solutions like JSS
* (allowing extends, mixins, reasoning, IDE integration, tree shaking etc.)
* - export to a CSS module for reuse in an outer context
*
*
* Please note that the HTML structure is purposely 'loose', allowing multiple design systems
* to be compatible
* with the CSS component.
* Note that every occurence of '::slotted(*)' can be rewritten to '> *' for use in an other
* context
*
* TODO: find best naming convention: https://en.bem.info/methodology/naming-convention/
* (react style would align better with JSS)
*/
/**
* {block} .form-field
*
* Structure:
* - {element} .form-field__label : a wrapper element around the projected label
* - {element} .form-field__help-text (optional) : a wrapper element around the projected
* help-text
* - {block} .input-group : a container around the input element, including prefixes and
* suffixes
* - {element} .form-field__feedback (optional) : a wrapper element around the projected
* (validation) feedback message
*
* Modifiers:
* - {state} .state-disabled : when .form-control (<input>, <textarea> etc.) has disabled set
* to true
* - {state} .state-focused: when .form-control (<input>, <textarea> etc.) <input> has focus
* - {state} .state-filled: whether <input> has a value
* - {state} .state-touched: whether the user had blurred the field once
* - {state} .state-dirty: whether the value has changed since initial value
*
* - {state} .state-invalid: when input has error(s) (regardless of whether they should be
* shown to the user)
* - {state} .state-error: when input has error(s) and this/these should be shown to the user
* - {state} .state-warning: when input has warning(s) and this/these should be shown to the
* user
* - {state} .state-info: when input has info feedback message(s) and this/these should be shown
* to the user
* - {state} .state-success: when input has success feedback message(s) and this/these should be
* shown to the user
*/
/**
* {block} .input-group
*
* Structure:
* - {element} .input-group__before (optional) : a prefix that resides outside the container
* - {element} .input-group__container : an inner container: this element contains all styling
* - {element} .input-group__prefix (optional) : a prefix that resides in the container,
* allowing it to be detectable as a :first-child
* - {element} .input-group__input : a wrapper around the form-control component
* - {block} .form-control : the actual input element (input/select/textarea)
* - {element} .input-group__suffix (optional) : a suffix that resides inside the container,
* allowing it to be detectable as a :last-child
* - {element} .input-group__bottom (optional) : placeholder element for additional styling
* (like an animated line for material design input)
* - {element} .input-group__after (optional) : a suffix that resides outside the container
*/
static get styles() {
return [
css`
/**********************
{block} .form-field
********************/
:host {
display: block;
}
:host(.state-disabled) {
pointer-events: none;
}
:host(.state-disabled) .form-field__label ::slotted(*),
:host(.state-disabled) .form-field__help-text ::slotted(*) {
color: var(--disabled-text-color, #adadad);
}
/***********************
{block} .input-group
*********************/
.input-group__container {
display: flex;
}
.input-group__input {
flex: 1;
display: flex;
}
/***** {state} .state-disabled *****/
:host(.state-disabled) .input-group ::slotted(slot='input') {
color: var(--disabled-text-color, #adadad);
}
/***********************
{block} .form-control
**********************/
.input-group__container > .input-group__input ::slotted(.form-control) {
flex: 1 1 auto;
margin: 0; /* remove input margin in Safari */
font-size: 100%; /* normalize default input font-size */
}
`,
];
}
// Returns dom references to all elements that should be referred to by field(s)
_getAriaDescriptionElements() {
return [this._helpTextNode, this._feedbackNode];
}
/**
* Meant for Application Developers wanting to add to aria-labelledby attribute.
* @param {Element} element
*/
addToAriaLabelledBy(element, customConfig = {}) {
const { idPrefix, reorder } = {
reorder: true,
...customConfig,
};
// eslint-disable-next-line no-param-reassign
element.id = element.id || `${idPrefix}-${this._inputId}`;
if (!this._ariaLabelledNodes.includes(element)) {
this._ariaLabelledNodes = [...this._ariaLabelledNodes, element];
// This value will be read when we need to reflect to attr
this.__reorderAriaLabelledNodes = Boolean(reorder);
}
}
/**
* Meant for Application Developers wanting to add to aria-describedby attribute.
* @param {Element} element
*/
addToAriaDescribedBy(element, customConfig = {}) {
const { idPrefix, reorder } = {
// chronologically sorts children of host element('this')
reorder: true,
...customConfig,
};
// eslint-disable-next-line no-param-reassign
element.id = element.id || `${idPrefix}-${this._inputId}`;
if (!this._ariaDescribedNodes.includes(element)) {
this._ariaDescribedNodes = [...this._ariaDescribedNodes, element];
// This value will be read when we need to reflect to attr
this.__reorderAriaDescribedNodes = Boolean(reorder);
}
}
__getDirectSlotChild(slotName) {
return [...this.children].find(el => el.slot === slotName);
}
},
);