overleaf/server-ce/test/helpers/waitUntilScrollingFinished.ts

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export function waitUntilScrollingFinished(selector: string, start = -1) {
const pollSlow = 100
const pollFast = 10
const deadline =
performance.now() + Cypress.config('defaultCommandTimeout') - pollSlow * 2
return cy.get(selector).then(el => {
cy.log(
`waiting until scrolling finished for ${selector}, starting from ${start}`
)
return new Cypress.Promise<number>((resolve, reject) => {
const waitForStable = (prev: number, stableFor: number) => {
if (performance.now() > deadline) {
return reject(new Error('timeout waiting for scrolling to finish'))
}
const current = el.scrollTop()!
if (current !== prev) {
setTimeout(() => waitForStable(current, 0), pollFast)
} else if (stableFor < 5) {
setTimeout(() => waitForStable(current, stableFor + 1), pollFast)
} else {
resolve(current)
}
}
const waitForChange = () => {
if (performance.now() > deadline) {
return reject(new Error('timeout waiting for scrolling to start'))
}
const current = el.scrollTop()!
if (current === start) {
setTimeout(() => waitForChange(), pollSlow)
} else {
setTimeout(() => waitForStable(current, 0), pollFast)
}
}
waitForChange()
})
})
}