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normalizeHighlightRange.ts
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normalizeHighlightRange.ts
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export function extendRangeToWordBoundaries(range: Range): void {
const { nodeValue: startValue } = range.startContainer
const { nodeValue: endValue } = range.endContainer
const noWordSnap = disableWordSnap(range.toString())
const startOffset = noWordSnap ? range.startOffset : findNextWord(range.startOffset, false, startValue)
const endOffset = noWordSnap ? range.endOffset : findNextWord(range.endOffset, true, endValue)
try {
range.setStart(range.startContainer, startOffset)
range.setEnd(range.endContainer, endOffset)
} catch {
console.warn('Unable to snap selection to the next word')
}
}
function disableWordSnap(str: string): boolean {
// For CJK languages we don't attempt word snapping
if (str.match(/[\u3131-\uD79D]/ugi)) {
return true
}
return false
}
const isWhitespace = (c?: string): boolean => {
return !!c && /\u2014|\u2013|,|\s/.test(c);
}
function findNextWord(
start: number,
forward: boolean,
str?: string | null
): number {
if (!str) {
return start
}
const chars = str.split('')
let i = start
if (forward) {
if (isWhitespace(chars[i - 1])) {
return i - 1
}
while (i < str.length) {
if (isWhitespace(chars[i])) {
return i
}
i++
}
} else {
if (isWhitespace(chars[i])) {
return i + 1
}
while (i > 0) {
if (isWhitespace(chars[i - 1])) {
return i
}
i--
}
}
return i
}