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Preserve default scroll #13

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1c673e8
Apply npm audit fix
knuton Sep 16, 2025
2879df0
Bump major version of cypress to 15
knuton Sep 16, 2025
f6b1e07
Rename test fixture for preventing scroll
knuton Sep 16, 2025
c9cfb85
[WIP] Preserve default action when not handling user action
knuton Sep 16, 2025
d58ba99
cypress does not have async/await slash return promises
knuton Sep 16, 2025
7001c14
initial scroll position may not be 0
knuton Sep 16, 2025
c7d47e8
instrument the tests
knuton Sep 16, 2025
aeba664
make sure to prevent scroll for debug
knuton Sep 16, 2025
d69ff87
test precondition
knuton Sep 16, 2025
c3840ff
Push booleans down in tree
knuton Sep 16, 2025
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18 changes: 17 additions & 1 deletion cypress/e2e/spec.cy.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -261,8 +261,24 @@ describe("focus-shift spec", () => {
])
)

it("preserves scroll as default action", function () {
cy.visit("./cypress/fixtures/default-action-scroll.html")
const getScrollTop = () => cy.document().then((doc) => doc.scrollingElement.scrollTop)

getScrollTop().then(initialScrollTop => {
expect(initialScrollTop).to.equal(0)
cy
.get("body").trigger("keydown", keyevent({ key: "ArrowDown" }))
.then(() => getScrollTop().then((scrollTop) => expect(scrollTop).to.equal(1)))
.then(() => cy.get("#first-button").trigger("keydown", keyevent({ key: "ArrowDown" })))
.then(() => getScrollTop().then((scrollTop) => expect(scrollTop).to.equal(2)))
.then(() => cy.get("#second-button").trigger("keydown", keyevent({ key: "ArrowDown" })))
.then(() => getScrollTop().then((scrollTop) => expect(scrollTop).to.not.equal(3)))
})
})

it("allows preventing scroll", function () {
cy.visit("./cypress/fixtures/scroll.html")
cy.visit("./cypress/fixtures/prevent-scroll.html")
const getScrollLeft = () => cy.document().then((doc) => doc.scrollingElement.scrollLeft)
function testScroll(id, assert) {
getScrollLeft().then((scrollLeftBefore) => {
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18 changes: 18 additions & 0 deletions cypress/fixtures/default-action-scroll.html
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Original file line number Diff line number Diff line change
@@ -0,0 +1,18 @@
<!doctype html>
<html lang="en">
<head>
<meta charset="UTF-8" />
<link rel="stylesheet" href="styles.css" />
</head>
<body class="rows">
<div class="nav-group" style="height: 100vh">
<button id="first-button" data-focus-prevent-scroll>First Button</button>
<button id="second-button" data-focus-prevent-scroll>Second Button</button>
</div>

<footer>
Important information in footer.
</footer>
<script src="../../index.js"></script>
</body>
</html>
0 cypress/fixtures/scroll.html → cypress/fixtures/prevent-scroll.html
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22 changes: 16 additions & 6 deletions index.js
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Original file line number Diff line number Diff line change
Expand Up @@ -43,8 +43,13 @@ function handleKeyDown(event) {
shiftFocusEvent
)
} else {
event.preventDefault()
handleUserDirection(KEY_TO_DIRECTION[event.key])
const wasHandled = handleUserDirection(KEY_TO_DIRECTION[event.key])

if (wasHandled) {
// Prevent default action only if we found a candidate to shift focus to,
// otherwise maintain browser's default behaviour (e.g. scroll).
event.preventDefault()
}
}
logging.groupEnd()
}
Expand All @@ -54,21 +59,23 @@ function handleKeyDown(event) {
* Handle a user's request for focus shift.
*
* @param {Direction} direction
* @returns {void}
* @returns {boolean} - Whether a spatial navigation action was performed
*/
function handleUserDirection(direction) {
const container = getBlockingElement()
const activeElement = getActiveElement(container)

if (activeElement == null) {
focusInitial(direction, container)
return
return true
}

const candidates = getFocusCandidates(direction, activeElement, container)
if (candidates.length > 0) {
performMove(direction, activeElement.getBoundingClientRect(), candidates)
return performMove(direction, activeElement.getBoundingClientRect(), candidates)
}

return false
}

/**
Expand Down Expand Up @@ -234,7 +241,7 @@ function getFocusCandidates(direction, activeElement, container) {
* @param {Direction} direction
* @param {DOMRect} originRect - The bounding box of the element that has focus at the time the move is initiated
* @param {Array<AnnotatedElement>} candidates - The candidates from which to pick
* @returns {void}
* @returns {boolean} - Whether a move has been performed
*/
function performMove(direction, originRect, candidates) {
logging.debug("performMove", direction, originRect, candidates)
Expand All @@ -254,6 +261,9 @@ function performMove(direction, originRect, candidates) {
)
if (bestCandidate != null) {
applyFocus(direction, originRect, bestCandidate.element)
return true
} else {
return false
}
}

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