José Almeida
43 lines
1.5 KiB
TypeScript
43 lines
1.5 KiB
TypeScript
export const CHAT_TEXT_DURATION_MS = 140;
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export type TextRun = { start: number; end: number; receivedAt: number };
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/** Keep only recent append ranges; rewrites have no reliable reveal boundary. */
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export function appendedTextRuns(
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previous: string,
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next: string,
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runs: TextRun[],
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now: number,
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): TextRun[] {
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if (!next.startsWith(previous)) return [];
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const active = runs.filter((run) => now - run.receivedAt < CHAT_TEXT_DURATION_MS);
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if (next.length === previous.length) return active;
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const last = active.at(-1);
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if (last && last.end === previous.length && now - last.receivedAt < 16) {
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return [...active.slice(0, -1), { ...last, end: next.length }];
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}
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return [...active, { start: previous.length, end: next.length, receivedAt: now }];
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}
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export type MotionTextPart = { text: string; receivedAt?: number };
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export function splitMotionText(
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value: string,
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offset: number | undefined,
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source: string,
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runs: TextRun[],
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): MotionTextPart[] {
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if (offset === undefined || source.slice(offset, offset + value.length) !== value)
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return [{ text: value }];
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const parts: MotionTextPart[] = [];
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let cursor = 0;
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for (const run of runs) {
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const start = Math.max(cursor, run.start - offset);
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const end = Math.min(value.length, run.end - offset);
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if (start >= end) continue;
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if (start > cursor) parts.push({ text: value.slice(cursor, start) });
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parts.push({ text: value.slice(start, end), receivedAt: run.receivedAt });
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cursor = end;
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}
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if (cursor < value.length) parts.push({ text: value.slice(cursor) });
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return parts;
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}
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