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