44 lines
1.1 KiB
TypeScript
44 lines
1.1 KiB
TypeScript
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// API for working with changes to document text
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/** Denotes a region in the document, based on character indicices
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*/
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export type Range = {
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/** The starting index of the span, 0-based, inclusive
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*/
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from: number;
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/** The ending index of the span, 0-based, exclusive
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*/
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to: number;
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};
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/** A modification to the document */
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export type TextChange = {
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/** The new text */
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inserted: string;
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/** The modified range **before** this change took effect.
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*
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* Example: "aaabbbccc" => "aaaccc", oldRange is [3, 6)
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*/
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oldRange: Range;
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/** The modified range **after** this change took effect.
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*
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* Example: "aaabbbccc" => "aaaccc", newRange is [3, 3)
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*/
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newRange: Range;
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};
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/** Get this distance between the start and end of a range */
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export function rangeLength(range: Range): number {
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return range.to - range.from;
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}
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export function rangesOverlap(a: Range, b: Range): boolean {
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// `b.from >= a.to` => "b" starts after "a"
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// `a.from >= b.to` => "b" ends before "a"
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// if neither is true these two ranges must overlap
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return !(b.from >= a.to || a.from >= b.to);
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}
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