26 lines
786 B
TypeScript
26 lines
786 B
TypeScript
import diff, { DELETE, EQUAL, INSERT } from "fast-diff";
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import type { ChangeSpec } from "@codemirror/state";
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export function diffAndPrepareChanges(
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oldString: string,
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newString: string,
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): ChangeSpec[] {
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// Use the fast-diff library to compute the changes
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const diffs = diff(oldString, newString);
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// Convert the diffs to CodeMirror transactions
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let startIndex = 0;
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const changes: ChangeSpec[] = [];
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for (const part of diffs) {
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if (part[0] === INSERT) {
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changes.push({ from: startIndex, insert: part[1] });
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} else if (part[0] === EQUAL) {
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startIndex += part[1].length;
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} else if (part[0] === DELETE) {
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changes.push({ from: startIndex, to: startIndex + part[1].length });
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startIndex += part[1].length;
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}
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}
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return changes;
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}
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