role-helpers.js
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"use strict";
Object.defineProperty(exports, "__esModule", {
value: true
});
exports.getRoles = getRoles;
exports.getImplicitAriaRoles = getImplicitAriaRoles;
exports.isSubtreeInaccessible = isSubtreeInaccessible;
exports.prettyRoles = prettyRoles;
exports.isInaccessible = isInaccessible;
exports.computeAriaSelected = computeAriaSelected;
exports.computeAriaChecked = computeAriaChecked;
exports.computeAriaPressed = computeAriaPressed;
exports.computeAriaExpanded = computeAriaExpanded;
exports.computeHeadingLevel = computeHeadingLevel;
exports.logRoles = void 0;
var _ariaQuery = require("aria-query");
var _domAccessibilityApi = require("dom-accessibility-api");
var _prettyDom = require("./pretty-dom");
var _config = require("./config");
const elementRoleList = buildElementRoleList(_ariaQuery.elementRoles);
/**
* @param {Element} element -
* @returns {boolean} - `true` if `element` and its subtree are inaccessible
*/
function isSubtreeInaccessible(element) {
if (element.hidden === true) {
return true;
}
if (element.getAttribute('aria-hidden') === 'true') {
return true;
}
const window = element.ownerDocument.defaultView;
if (window.getComputedStyle(element).display === 'none') {
return true;
}
return false;
}
/**
* Partial implementation https://www.w3.org/TR/wai-aria-1.2/#tree_exclusion
* which should only be used for elements with a non-presentational role i.e.
* `role="none"` and `role="presentation"` will not be excluded.
*
* Implements aria-hidden semantics (i.e. parent overrides child)
* Ignores "Child Presentational: True" characteristics
*
* @param {Element} element -
* @param {object} [options] -
* @param {function (element: Element): boolean} options.isSubtreeInaccessible -
* can be used to return cached results from previous isSubtreeInaccessible calls
* @returns {boolean} true if excluded, otherwise false
*/
function isInaccessible(element, options = {}) {
const {
isSubtreeInaccessible: isSubtreeInaccessibleImpl = isSubtreeInaccessible
} = options;
const window = element.ownerDocument.defaultView; // since visibility is inherited we can exit early
if (window.getComputedStyle(element).visibility === 'hidden') {
return true;
}
let currentElement = element;
while (currentElement) {
if (isSubtreeInaccessibleImpl(currentElement)) {
return true;
}
currentElement = currentElement.parentElement;
}
return false;
}
function getImplicitAriaRoles(currentNode) {
// eslint bug here:
// eslint-disable-next-line no-unused-vars
for (const {
match,
roles
} of elementRoleList) {
if (match(currentNode)) {
return [...roles];
}
}
return [];
}
function buildElementRoleList(elementRolesMap) {
function makeElementSelector({
name,
attributes
}) {
return `${name}${attributes.map(({
name: attributeName,
value,
constraints = []
}) => {
const shouldNotExist = constraints.indexOf('undefined') !== -1;
if (shouldNotExist) {
return `:not([${attributeName}])`;
} else if (value) {
return `[${attributeName}="${value}"]`;
} else {
return `[${attributeName}]`;
}
}).join('')}`;
}
function getSelectorSpecificity({
attributes = []
}) {
return attributes.length;
}
function match(element) {
return node => {
let {
attributes = []
} = element; // https://github.com/testing-library/dom-testing-library/issues/814
const typeTextIndex = attributes.findIndex(attribute => attribute.value && attribute.name === 'type' && attribute.value === 'text');
if (typeTextIndex >= 0) {
// not using splice to not mutate the attributes array
attributes = [...attributes.slice(0, typeTextIndex), ...attributes.slice(typeTextIndex + 1)];
if (node.type !== 'text') {
return false;
}
}
return node.matches(makeElementSelector({ ...element,
attributes
}));
};
}
let result = []; // eslint bug here:
// eslint-disable-next-line no-unused-vars
for (const [element, roles] of elementRolesMap.entries()) {
result = [...result, {
match: match(element),
roles: Array.from(roles),
specificity: getSelectorSpecificity(element)
}];
}
return result.sort(function ({
specificity: leftSpecificity
}, {
specificity: rightSpecificity
}) {
return rightSpecificity - leftSpecificity;
});
}
function getRoles(container, {
hidden = false
} = {}) {
function flattenDOM(node) {
return [node, ...Array.from(node.children).reduce((acc, child) => [...acc, ...flattenDOM(child)], [])];
}
return flattenDOM(container).filter(element => {
return hidden === false ? isInaccessible(element) === false : true;
}).reduce((acc, node) => {
let roles = []; // TODO: This violates html-aria which does not allow any role on every element
if (node.hasAttribute('role')) {
roles = node.getAttribute('role').split(' ').slice(0, 1);
} else {
roles = getImplicitAriaRoles(node);
}
return roles.reduce((rolesAcc, role) => Array.isArray(rolesAcc[role]) ? { ...rolesAcc,
[role]: [...rolesAcc[role], node]
} : { ...rolesAcc,
[role]: [node]
}, acc);
}, {});
}
function prettyRoles(dom, {
hidden
}) {
const roles = getRoles(dom, {
hidden
}); // We prefer to skip generic role, we don't recommend it
return Object.entries(roles).filter(([role]) => role !== 'generic').map(([role, elements]) => {
const delimiterBar = '-'.repeat(50);
const elementsString = elements.map(el => {
const nameString = `Name "${(0, _domAccessibilityApi.computeAccessibleName)(el, {
computedStyleSupportsPseudoElements: (0, _config.getConfig)().computedStyleSupportsPseudoElements
})}":\n`;
const domString = (0, _prettyDom.prettyDOM)(el.cloneNode(false));
return `${nameString}${domString}`;
}).join('\n\n');
return `${role}:\n\n${elementsString}\n\n${delimiterBar}`;
}).join('\n');
}
const logRoles = (dom, {
hidden = false
} = {}) => console.log(prettyRoles(dom, {
hidden
}));
/**
* @param {Element} element -
* @returns {boolean | undefined} - false/true if (not)selected, undefined if not selectable
*/
exports.logRoles = logRoles;
function computeAriaSelected(element) {
// implicit value from html-aam mappings: https://www.w3.org/TR/html-aam-1.0/#html-attribute-state-and-property-mappings
// https://www.w3.org/TR/html-aam-1.0/#details-id-97
if (element.tagName === 'OPTION') {
return element.selected;
} // explicit value
return checkBooleanAttribute(element, 'aria-selected');
}
/**
* @param {Element} element -
* @returns {boolean | undefined} - false/true if (not)checked, undefined if not checked-able
*/
function computeAriaChecked(element) {
// implicit value from html-aam mappings: https://www.w3.org/TR/html-aam-1.0/#html-attribute-state-and-property-mappings
// https://www.w3.org/TR/html-aam-1.0/#details-id-56
// https://www.w3.org/TR/html-aam-1.0/#details-id-67
if ('indeterminate' in element && element.indeterminate) {
return undefined;
}
if ('checked' in element) {
return element.checked;
} // explicit value
return checkBooleanAttribute(element, 'aria-checked');
}
/**
* @param {Element} element -
* @returns {boolean | undefined} - false/true if (not)pressed, undefined if not press-able
*/
function computeAriaPressed(element) {
// https://www.w3.org/TR/wai-aria-1.1/#aria-pressed
return checkBooleanAttribute(element, 'aria-pressed');
}
/**
* @param {Element} element -
* @returns {boolean | undefined} - false/true if (not)expanded, undefined if not expand-able
*/
function computeAriaExpanded(element) {
// https://www.w3.org/TR/wai-aria-1.1/#aria-expanded
return checkBooleanAttribute(element, 'aria-expanded');
}
function checkBooleanAttribute(element, attribute) {
const attributeValue = element.getAttribute(attribute);
if (attributeValue === 'true') {
return true;
}
if (attributeValue === 'false') {
return false;
}
return undefined;
}
/**
* @param {Element} element -
* @returns {number | undefined} - number if implicit heading or aria-level present, otherwise undefined
*/
function computeHeadingLevel(element) {
// https://w3c.github.io/html-aam/#el-h1-h6
// https://w3c.github.io/html-aam/#el-h1-h6
// explicit aria-level value
// https://www.w3.org/TR/wai-aria-1.2/#aria-level
const ariaLevelAttribute = element.getAttribute('aria-level') && Number(element.getAttribute('aria-level'));
return ariaLevelAttribute || {
H1: 1,
H2: 2,
H3: 3,
H4: 4,
H5: 5,
H6: 6
}[element.tagName];
}