Convert Jira Task Title to a git branch name and copy to clipboard

JiraTitleToClipboard.js

/*
Played around so it works from DevTools console too.

EDIT:
After making this I went and wrote an extension for Chromium based browsers "Jira Task Title to Git Branch (Clipboard)"
Its code is totally free for abuse: https://github.com/mathmul/chr-ext-jira-task-title-to-git-branch
*/
await (async function copyBranchNameToClipboard(branchType = 'feature', timeToFallbackMethod = Infinity) {

    const getJiraTaskKey = () =>
        window.location.href.match(/\/browse\/([A-Z]+-\d+)/)?.[1] + '-' || ''
    
    const slugifyText = text => text
        .normalize('NFKD')
        .replace(/[\u0300-\u036f]/g, '')
        .toLowerCase()
        .replace(/[^a-z0-9 -]/g, '-')
        .replace(/\s+/g, '-')
        .replace(/-+/g, '-')
        .replace(/^-+|-+$/g, '')

    const copyToClipboard = (text, timeToFallbackMethod) => new Promise((resolve, reject) => {
        const storage = document.createElement('textarea')
        storage.style.position = 'fixed'
        storage.style.top = '0'
        storage.style.left = '0'
        storage.style.width = '2em'
        storage.style.height = '2em'
        storage.style.padding = '0'
        storage.style.border = 'none'
        storage.style.outline = 'none'
        storage.style.boxShadow = 'none'
        storage.style.background = 'transparent'
        
        storage.value = text
        document.body.appendChild(storage)
        
        storage.focus()
        storage.select()
        storage.setSelectionRange(0, 99999)

        const handleCopy = async () => {
            clearTimeout(fallbackTimeout)
            try {
                await navigator.clipboard.writeText(storage.value)
                resolve(storage.value)
            } catch (err) {
                document.execCommand('copy')
                    ? resolve(storage.value)
                    : reject(err)
            } finally {
                document.body.removeChild(storage)
                window.removeEventListener('focus', handleCopy)
            }
        }


        const fallbackTimeout = timeToFallbackMethod <= 2_147_483_647 && setTimeout(() => {
            console.log(`Falling back to document.execCommand after ${Math.round(timeToFallbackMethod / 1000)} seconds`)
            if (document.execCommand('copy')) {
                resolve(storage.value)
            } else {
                const err = new Error('Failed with document.execCommand after timeout')
                console.error(err)
                reject(err)
            }
            document.body.removeChild(storage)
            window.removeEventListener('focus', handleCopy)
        }, Math.min(timeToFallbackMethod))

        window.addEventListener('focus', handleCopy)
        console.log("Hit <Tab> to give focus back to document (or we will face a DOMException)")
    })

    const jiraKey = getJiraTaskKey()
    const taskTitle = document.querySelector('h1').innerText
    const slugifiedTitle = slugifyText(taskTitle)
    const branchName = `${branchType}/${jiraKey}${slugifiedTitle}`

    return await copyToClipboard(branchName, timeToFallbackMethod)
        .then(() => `Branch name copied to clipboard: ${branchName}`)
        .catch(err => `Failed to copy branch name: ${err}`)
})('feature', 0)