// NOTE: separate `:not()` selectors has broader browser support than the newer | |
// `:not([inert], [inert] *)` (Feb 2023) | |
// CAREFUL: JSDom does not support `:not([inert] *)` as a selector; using it causes | |
// the entire query to fail, resulting in no nodes found, which will break a lot | |
// of things... so we have to rely on JS to identify nodes inside an inert container | |
const candidateSelectors = [ | |
'input:not([inert])', | |
'select:not([inert])', | |
'textarea:not([inert])', | |
'a[href]:not([inert])', | |
'button:not([inert])', | |
'[tabindex]:not(slot):not([inert])', | |
'audio[controls]:not([inert])', | |
'video[controls]:not([inert])', | |
'[contenteditable]:not([contenteditable="false"]):not([inert])', | |
'details>summary:first-of-type:not([inert])', | |
'details:not([inert])', | |
]; | |
const candidateSelector = /* #__PURE__ */ candidateSelectors.join(','); | |
const NoElement = typeof Element === 'undefined'; | |
const matches = NoElement | |
? function () {} | |
: Element.prototype.matches || | |
Element.prototype.msMatchesSelector || | |
Element.prototype.webkitMatchesSelector; | |
const getRootNode = | |
!NoElement && Element.prototype.getRootNode | |
? (element) => element?.getRootNode?.() | |
: (element) => element?.ownerDocument; | |
/** | |
* Determines if a node is inert or in an inert ancestor. | |
* @param {Element} [node] | |
* @param {boolean} [lookUp] If true and `node` is not inert, looks up at ancestors to | |
* see if any of them are inert. If false, only `node` itself is considered. | |
* @returns {boolean} True if inert itself or by way of being in an inert ancestor. | |
* False if `node` is falsy. | |
*/ | |
const isInert = function (node, lookUp = true) { | |
// CAREFUL: JSDom does not support inert at all, so we can't use the `HTMLElement.inert` | |
// JS API property; we have to check the attribute, which can either be empty or 'true'; | |
// if it's `null` (not specified) or 'false', it's an active element | |
const inertAtt = node?.getAttribute?.('inert'); | |
const inert = inertAtt === '' || inertAtt === 'true'; | |
// NOTE: this could also be handled with `node.matches('[inert], :is([inert] *)')` | |
// if it weren't for `matches()` not being a function on shadow roots; the following | |
// code works for any kind of node | |
// CAREFUL: JSDom does not appear to support certain selectors like `:not([inert] *)` | |
// so it likely would not support `:is([inert] *)` either... | |
const result = inert || (lookUp && node && isInert(node.parentNode)); // recursive | |
return result; | |
}; | |
/** | |
* Determines if a node's content is editable. | |
* @param {Element} [node] | |
* @returns True if it's content-editable; false if it's not or `node` is falsy. | |
*/ | |
const isContentEditable = function (node) { | |
// CAREFUL: JSDom does not support the `HTMLElement.isContentEditable` API so we have | |
// to use the attribute directly to check for this, which can either be empty or 'true'; | |
// if it's `null` (not specified) or 'false', it's a non-editable element | |
const attValue = node?.getAttribute?.('contenteditable'); | |
return attValue === '' || attValue === 'true'; | |
}; | |
/** | |
* @param {Element} el container to check in | |
* @param {boolean} includeContainer add container to check | |
* @param {(node: Element) => boolean} filter filter candidates | |
* @returns {Element[]} | |
*/ | |
const getCandidates = function (el, includeContainer, filter) { | |
// even if `includeContainer=false`, we still have to check it for inertness because | |
// if it's inert, all its children are inert | |
if (isInert(el)) { | |
return []; | |
} | |
let candidates = Array.prototype.slice.apply( | |
el.querySelectorAll(candidateSelector) | |
); | |
if (includeContainer && matches.call(el, candidateSelector)) { | |
candidates.unshift(el); | |
} | |
candidates = candidates.filter(filter); | |
return candidates; | |
}; | |
/** | |
* @callback GetShadowRoot | |
* @param {Element} element to check for shadow root | |
* @returns {ShadowRoot|boolean} ShadowRoot if available or boolean indicating if a shadowRoot is attached but not available. | |
*/ | |
/** | |
* @callback ShadowRootFilter | |
* @param {Element} shadowHostNode the element which contains shadow content | |
* @returns {boolean} true if a shadow root could potentially contain valid candidates. | |
*/ | |
/** | |
* @typedef {Object} CandidateScope | |
* @property {Element} scopeParent contains inner candidates | |
* @property {Element[]} candidates list of candidates found in the scope parent | |
*/ | |
/** | |
* @typedef {Object} IterativeOptions | |
* @property {GetShadowRoot|boolean} getShadowRoot true if shadow support is enabled; falsy if not; | |
* if a function, implies shadow support is enabled and either returns the shadow root of an element | |
* or a boolean stating if it has an undisclosed shadow root | |
* @property {(node: Element) => boolean} filter filter candidates | |
* @property {boolean} flatten if true then result will flatten any CandidateScope into the returned list | |
* @property {ShadowRootFilter} shadowRootFilter filter shadow roots; | |
*/ | |
/** | |
* @param {Element[]} elements list of element containers to match candidates from | |
* @param {boolean} includeContainer add container list to check | |
* @param {IterativeOptions} options | |
* @returns {Array.<Element|CandidateScope>} | |
*/ | |
const getCandidatesIteratively = function ( | |
elements, | |
includeContainer, | |
options | |
) { | |
const candidates = []; | |
const elementsToCheck = Array.from(elements); | |
while (elementsToCheck.length) { | |
const element = elementsToCheck.shift(); | |
if (isInert(element, false)) { | |
// no need to look up since we're drilling down | |
// anything inside this container will also be inert | |
continue; | |
} | |
if (element.tagName === 'SLOT') { | |
// add shadow dom slot scope (slot itself cannot be focusable) | |
const assigned = element.assignedElements(); | |
const content = assigned.length ? assigned : element.children; | |
const nestedCandidates = getCandidatesIteratively(content, true, options); | |
if (options.flatten) { | |
candidates.push(...nestedCandidates); | |
} else { | |
candidates.push({ | |
scopeParent: element, | |
candidates: nestedCandidates, | |
}); | |
} | |
} else { | |
// check candidate element | |
const validCandidate = matches.call(element, candidateSelector); | |
if ( | |
validCandidate && | |
options.filter(element) && | |
(includeContainer || !elements.includes(element)) | |
) { | |
candidates.push(element); | |
} | |
// iterate over shadow content if possible | |
const shadowRoot = | |
element.shadowRoot || | |
// check for an undisclosed shadow | |
(typeof options.getShadowRoot === 'function' && | |
options.getShadowRoot(element)); | |
// no inert look up because we're already drilling down and checking for inertness | |
// on the way down, so all containers to this root node should have already been | |
// vetted as non-inert | |
const validShadowRoot = | |
!isInert(shadowRoot, false) && | |
(!options.shadowRootFilter || options.shadowRootFilter(element)); | |
if (shadowRoot && validShadowRoot) { | |
// add shadow dom scope IIF a shadow root node was given; otherwise, an undisclosed | |
// shadow exists, so look at light dom children as fallback BUT create a scope for any | |
// child candidates found because they're likely slotted elements (elements that are | |
// children of the web component element (which has the shadow), in the light dom, but | |
// slotted somewhere _inside_ the undisclosed shadow) -- the scope is created below, | |
// _after_ we return from this recursive call | |
const nestedCandidates = getCandidatesIteratively( | |
shadowRoot === true ? element.children : shadowRoot.children, | |
true, | |
options | |
); | |
if (options.flatten) { | |
candidates.push(...nestedCandidates); | |
} else { | |
candidates.push({ | |
scopeParent: element, | |
candidates: nestedCandidates, | |
}); | |
} | |
} else { | |
// there's not shadow so just dig into the element's (light dom) children | |
// __without__ giving the element special scope treatment | |
elementsToCheck.unshift(...element.children); | |
} | |
} | |
} | |
return candidates; | |
}; | |
/** | |
* @private | |
* Determines if the node has an explicitly specified `tabindex` attribute. | |
* @param {HTMLElement} node | |
* @returns {boolean} True if so; false if not. | |
*/ | |
const hasTabIndex = function (node) { | |
return !isNaN(parseInt(node.getAttribute('tabindex'), 10)); | |
}; | |
/** | |
* Determine the tab index of a given node. | |
* @param {HTMLElement} node | |
* @returns {number} Tab order (negative, 0, or positive number). | |
* @throws {Error} If `node` is falsy. | |
*/ | |
const getTabIndex = function (node) { | |
if (!node) { | |
throw new Error('No node provided'); | |
} | |
if (node.tabIndex < 0) { | |
// in Chrome, <details/>, <audio controls/> and <video controls/> elements get a default | |
// `tabIndex` of -1 when the 'tabindex' attribute isn't specified in the DOM, | |
// yet they are still part of the regular tab order; in FF, they get a default | |
// `tabIndex` of 0; since Chrome still puts those elements in the regular tab | |
// order, consider their tab index to be 0. | |
// Also browsers do not return `tabIndex` correctly for contentEditable nodes; | |
// so if they don't have a tabindex attribute specifically set, assume it's 0. | |
if ( | |
(/^(AUDIO|VIDEO|DETAILS)$/.test(node.tagName) || | |
isContentEditable(node)) && | |
!hasTabIndex(node) | |
) { | |
return 0; | |
} | |
} | |
return node.tabIndex; | |
}; | |
/** | |
* Determine the tab index of a given node __for sort order purposes__. | |
* @param {HTMLElement} node | |
* @param {boolean} [isScope] True for a custom element with shadow root or slot that, by default, | |
* has tabIndex -1, but needs to be sorted by document order in order for its content to be | |
* inserted into the correct sort position. | |
* @returns {number} Tab order (negative, 0, or positive number). | |
*/ | |
const getSortOrderTabIndex = function (node, isScope) { | |
const tabIndex = getTabIndex(node); | |
if (tabIndex < 0 && isScope && !hasTabIndex(node)) { | |
return 0; | |
} | |
return tabIndex; | |
}; | |
const sortOrderedTabbables = function (a, b) { | |
return a.tabIndex === b.tabIndex | |
? a.documentOrder - b.documentOrder | |
: a.tabIndex - b.tabIndex; | |
}; | |
const isInput = function (node) { | |
return node.tagName === 'INPUT'; | |
}; | |
const isHiddenInput = function (node) { | |
return isInput(node) && node.type === 'hidden'; | |
}; | |
const isDetailsWithSummary = function (node) { | |
const r = | |
node.tagName === 'DETAILS' && | |
Array.prototype.slice | |
.apply(node.children) | |
.some((child) => child.tagName === 'SUMMARY'); | |
return r; | |
}; | |
const getCheckedRadio = function (nodes, form) { | |
for (let i = 0; i < nodes.length; i++) { | |
if (nodes[i].checked && nodes[i].form === form) { | |
return nodes[i]; | |
} | |
} | |
}; | |
const isTabbableRadio = function (node) { | |
if (!node.name) { | |
return true; | |
} | |
const radioScope = node.form || getRootNode(node); | |
const queryRadios = function (name) { | |
return radioScope.querySelectorAll( | |
'input[type="radio"][name="' + name + '"]' | |
); | |
}; | |
let radioSet; | |
if ( | |
typeof window !== 'undefined' && | |
typeof window.CSS !== 'undefined' && | |
typeof window.CSS.escape === 'function' | |
) { | |
radioSet = queryRadios(window.CSS.escape(node.name)); | |
} else { | |
try { | |
radioSet = queryRadios(node.name); | |
} catch (err) { | |
// eslint-disable-next-line no-console | |
console.error( | |
'Looks like you have a radio button with a name attribute containing invalid CSS selector characters and need the CSS.escape polyfill: %s', | |
err.message | |
); | |
return false; | |
} | |
} | |
const checked = getCheckedRadio(radioSet, node.form); | |
return !checked || checked === node; | |
}; | |
const isRadio = function (node) { | |
return isInput(node) && node.type === 'radio'; | |
}; | |
const isNonTabbableRadio = function (node) { | |
return isRadio(node) && !isTabbableRadio(node); | |
}; | |
// determines if a node is ultimately attached to the window's document | |
const isNodeAttached = function (node) { | |
// The root node is the shadow root if the node is in a shadow DOM; some document otherwise | |
// (but NOT _the_ document; see second 'If' comment below for more). | |
// If rootNode is shadow root, it'll have a host, which is the element to which the shadow | |
// is attached, and the one we need to check if it's in the document or not (because the | |
// shadow, and all nodes it contains, is never considered in the document since shadows | |
// behave like self-contained DOMs; but if the shadow's HOST, which is part of the document, | |
// is hidden, or is not in the document itself but is detached, it will affect the shadow's | |
// visibility, including all the nodes it contains). The host could be any normal node, | |
// or a custom element (i.e. web component). Either way, that's the one that is considered | |
// part of the document, not the shadow root, nor any of its children (i.e. the node being | |
// tested). | |
// To further complicate things, we have to look all the way up until we find a shadow HOST | |
// that is attached (or find none) because the node might be in nested shadows... | |
// If rootNode is not a shadow root, it won't have a host, and so rootNode should be the | |
// document (per the docs) and while it's a Document-type object, that document does not | |
// appear to be the same as the node's `ownerDocument` for some reason, so it's safer | |
// to ignore the rootNode at this point, and use `node.ownerDocument`. Otherwise, | |
// using `rootNode.contains(node)` will _always_ be true we'll get false-positives when | |
// node is actually detached. | |
// NOTE: If `nodeRootHost` or `node` happens to be the `document` itself (which is possible | |
// if a tabbable/focusable node was quickly added to the DOM, focused, and then removed | |
// from the DOM as in https://github.com/focus-trap/focus-trap-react/issues/905), then | |
// `ownerDocument` will be `null`, hence the optional chaining on it. | |
let nodeRoot = node && getRootNode(node); | |
let nodeRootHost = nodeRoot?.host; | |
// in some cases, a detached node will return itself as the root instead of a document or | |
// shadow root object, in which case, we shouldn't try to look further up the host chain | |
let attached = false; | |
if (nodeRoot && nodeRoot !== node) { | |
attached = !!( | |
nodeRootHost?.ownerDocument?.contains(nodeRootHost) || | |
node?.ownerDocument?.contains(node) | |
); | |
while (!attached && nodeRootHost) { | |
// since it's not attached and we have a root host, the node MUST be in a nested shadow DOM, | |
// which means we need to get the host's host and check if that parent host is contained | |
// in (i.e. attached to) the document | |
nodeRoot = getRootNode(nodeRootHost); | |
nodeRootHost = nodeRoot?.host; | |
attached = !!nodeRootHost?.ownerDocument?.contains(nodeRootHost); | |
} | |
} | |
return attached; | |
}; | |
const isZeroArea = function (node) { | |
const { width, height } = node.getBoundingClientRect(); | |
return width === 0 && height === 0; | |
}; | |
const isHidden = function (node, { displayCheck, getShadowRoot }) { | |
// NOTE: visibility will be `undefined` if node is detached from the document | |
// (see notes about this further down), which means we will consider it visible | |
// (this is legacy behavior from a very long way back) | |
// NOTE: we check this regardless of `displayCheck="none"` because this is a | |
// _visibility_ check, not a _display_ check | |
if (getComputedStyle(node).visibility === 'hidden') { | |
return true; | |
} | |
const isDirectSummary = matches.call(node, 'details>summary:first-of-type'); | |
const nodeUnderDetails = isDirectSummary ? node.parentElement : node; | |
if (matches.call(nodeUnderDetails, 'details:not([open]) *')) { | |
return true; | |
} | |
if ( | |
!displayCheck || | |
displayCheck === 'full' || | |
displayCheck === 'legacy-full' | |
) { | |
if (typeof getShadowRoot === 'function') { | |
// figure out if we should consider the node to be in an undisclosed shadow and use the | |
// 'non-zero-area' fallback | |
const originalNode = node; | |
while (node) { | |
const parentElement = node.parentElement; | |
const rootNode = getRootNode(node); | |
if ( | |
parentElement && | |
!parentElement.shadowRoot && | |
getShadowRoot(parentElement) === true // check if there's an undisclosed shadow | |
) { | |
// node has an undisclosed shadow which means we can only treat it as a black box, so we | |
// fall back to a non-zero-area test | |
return isZeroArea(node); | |
} else if (node.assignedSlot) { | |
// iterate up slot | |
node = node.assignedSlot; | |
} else if (!parentElement && rootNode !== node.ownerDocument) { | |
// cross shadow boundary | |
node = rootNode.host; | |
} else { | |
// iterate up normal dom | |
node = parentElement; | |
} | |
} | |
node = originalNode; | |
} | |
// else, `getShadowRoot` might be true, but all that does is enable shadow DOM support | |
// (i.e. it does not also presume that all nodes might have undisclosed shadows); or | |
// it might be a falsy value, which means shadow DOM support is disabled | |
// Since we didn't find it sitting in an undisclosed shadow (or shadows are disabled) | |
// now we can just test to see if it would normally be visible or not, provided it's | |
// attached to the main document. | |
// NOTE: We must consider case where node is inside a shadow DOM and given directly to | |
// `isTabbable()` or `isFocusable()` -- regardless of `getShadowRoot` option setting. | |
if (isNodeAttached(node)) { | |
// this works wherever the node is: if there's at least one client rect, it's | |
// somehow displayed; it also covers the CSS 'display: contents' case where the | |
// node itself is hidden in place of its contents; and there's no need to search | |
// up the hierarchy either | |
return !node.getClientRects().length; | |
} | |
// Else, the node isn't attached to the document, which means the `getClientRects()` | |
// API will __always__ return zero rects (this can happen, for example, if React | |
// is used to render nodes onto a detached tree, as confirmed in this thread: | |
// https://github.com/facebook/react/issues/9117#issuecomment-284228870) | |
// | |
// It also means that even window.getComputedStyle(node).display will return `undefined` | |
// because styles are only computed for nodes that are in the document. | |
// | |
// NOTE: THIS HAS BEEN THE CASE FOR YEARS. It is not new, nor is it caused by tabbable | |
// somehow. Though it was never stated officially, anyone who has ever used tabbable | |
// APIs on nodes in detached containers has actually implicitly used tabbable in what | |
// was later (as of v5.2.0 on Apr 9, 2021) called `displayCheck="none"` mode -- essentially | |
// considering __everything__ to be visible because of the innability to determine styles. | |
// | |
// v6.0.0: As of this major release, the default 'full' option __no longer treats detached | |
// nodes as visible with the 'none' fallback.__ | |
if (displayCheck !== 'legacy-full') { | |
return true; // hidden | |
} | |
// else, fallback to 'none' mode and consider the node visible | |
} else if (displayCheck === 'non-zero-area') { | |
// NOTE: Even though this tests that the node's client rect is non-zero to determine | |
// whether it's displayed, and that a detached node will __always__ have a zero-area | |
// client rect, we don't special-case for whether the node is attached or not. In | |
// this mode, we do want to consider nodes that have a zero area to be hidden at all | |
// times, and that includes attached or not. | |
return isZeroArea(node); | |
} | |
// visible, as far as we can tell, or per current `displayCheck=none` mode, we assume | |
// it's visible | |
return false; | |
}; | |
// form fields (nested) inside a disabled fieldset are not focusable/tabbable | |
// unless they are in the _first_ <legend> element of the top-most disabled | |
// fieldset | |
const isDisabledFromFieldset = function (node) { | |
if (/^(INPUT|BUTTON|SELECT|TEXTAREA)$/.test(node.tagName)) { | |
let parentNode = node.parentElement; | |
// check if `node` is contained in a disabled <fieldset> | |
while (parentNode) { | |
if (parentNode.tagName === 'FIELDSET' && parentNode.disabled) { | |
// look for the first <legend> among the children of the disabled <fieldset> | |
for (let i = 0; i < parentNode.children.length; i++) { | |
const child = parentNode.children.item(i); | |
// when the first <legend> (in document order) is found | |
if (child.tagName === 'LEGEND') { | |
// if its parent <fieldset> is not nested in another disabled <fieldset>, | |
// return whether `node` is a descendant of its first <legend> | |
return matches.call(parentNode, 'fieldset[disabled] *') | |
? true | |
: !child.contains(node); | |
} | |
} | |
// the disabled <fieldset> containing `node` has no <legend> | |
return true; | |
} | |
parentNode = parentNode.parentElement; | |
} | |
} | |
// else, node's tabbable/focusable state should not be affected by a fieldset's | |
// enabled/disabled state | |
return false; | |
}; | |
const isNodeMatchingSelectorFocusable = function (options, node) { | |
if ( | |
node.disabled || | |
// we must do an inert look up to filter out any elements inside an inert ancestor | |
// because we're limited in the type of selectors we can use in JSDom (see related | |
// note related to `candidateSelectors`) | |
isInert(node) || | |
isHiddenInput(node) || | |
isHidden(node, options) || | |
// For a details element with a summary, the summary element gets the focus | |
isDetailsWithSummary(node) || | |
isDisabledFromFieldset(node) | |
) { | |
return false; | |
} | |
return true; | |
}; | |
const isNodeMatchingSelectorTabbable = function (options, node) { | |
if ( | |
isNonTabbableRadio(node) || | |
getTabIndex(node) < 0 || | |
!isNodeMatchingSelectorFocusable(options, node) | |
) { | |
return false; | |
} | |
return true; | |
}; | |
const isValidShadowRootTabbable = function (shadowHostNode) { | |
const tabIndex = parseInt(shadowHostNode.getAttribute('tabindex'), 10); | |
if (isNaN(tabIndex) || tabIndex >= 0) { | |
return true; | |
} | |
// If a custom element has an explicit negative tabindex, | |
// browsers will not allow tab targeting said element's children. | |
return false; | |
}; | |
/** | |
* @param {Array.<Element|CandidateScope>} candidates | |
* @returns Element[] | |
*/ | |
const sortByOrder = function (candidates) { | |
const regularTabbables = []; | |
const orderedTabbables = []; | |
candidates.forEach(function (item, i) { | |
const isScope = !!item.scopeParent; | |
const element = isScope ? item.scopeParent : item; | |
const candidateTabindex = getSortOrderTabIndex(element, isScope); | |
const elements = isScope ? sortByOrder(item.candidates) : element; | |
if (candidateTabindex === 0) { | |
isScope | |
? regularTabbables.push(...elements) | |
: regularTabbables.push(element); | |
} else { | |
orderedTabbables.push({ | |
documentOrder: i, | |
tabIndex: candidateTabindex, | |
item: item, | |
isScope: isScope, | |
content: elements, | |
}); | |
} | |
}); | |
return orderedTabbables | |
.sort(sortOrderedTabbables) | |
.reduce((acc, sortable) => { | |
sortable.isScope | |
? acc.push(...sortable.content) | |
: acc.push(sortable.content); | |
return acc; | |
}, []) | |
.concat(regularTabbables); | |
}; | |
const tabbable = function (container, options) { | |
options = options || {}; | |
let candidates; | |
if (options.getShadowRoot) { | |
candidates = getCandidatesIteratively( | |
[container], | |
options.includeContainer, | |
{ | |
filter: isNodeMatchingSelectorTabbable.bind(null, options), | |
flatten: false, | |
getShadowRoot: options.getShadowRoot, | |
shadowRootFilter: isValidShadowRootTabbable, | |
} | |
); | |
} else { | |
candidates = getCandidates( | |
container, | |
options.includeContainer, | |
isNodeMatchingSelectorTabbable.bind(null, options) | |
); | |
} | |
return sortByOrder(candidates); | |
}; | |
const focusable = function (container, options) { | |
options = options || {}; | |
let candidates; | |
if (options.getShadowRoot) { | |
candidates = getCandidatesIteratively( | |
[container], | |
options.includeContainer, | |
{ | |
filter: isNodeMatchingSelectorFocusable.bind(null, options), | |
flatten: true, | |
getShadowRoot: options.getShadowRoot, | |
} | |
); | |
} else { | |
candidates = getCandidates( | |
container, | |
options.includeContainer, | |
isNodeMatchingSelectorFocusable.bind(null, options) | |
); | |
} | |
return candidates; | |
}; | |
const isTabbable = function (node, options) { | |
options = options || {}; | |
if (!node) { | |
throw new Error('No node provided'); | |
} | |
if (matches.call(node, candidateSelector) === false) { | |
return false; | |
} | |
return isNodeMatchingSelectorTabbable(options, node); | |
}; | |
const focusableCandidateSelector = /* #__PURE__ */ candidateSelectors | |
.concat('iframe') | |
.join(','); | |
const isFocusable = function (node, options) { | |
options = options || {}; | |
if (!node) { | |
throw new Error('No node provided'); | |
} | |
if (matches.call(node, focusableCandidateSelector) === false) { | |
return false; | |
} | |
return isNodeMatchingSelectorFocusable(options, node); | |
}; | |
export { tabbable, focusable, isTabbable, isFocusable, getTabIndex }; | |