Function Duration Invocations

1// A function-duration optimization can reduce p95/CPU/GB-hr. It does not by
2// itself reduce function invocation count unless the fix also adds CDN/static
3// response caching.
4
5export const metadata = {
6  id: 'function-duration-invocations',
7  description: 'Remove false claims that slow-route data-cache fixes reduce function invocation count.',
8};
9
10const STRING_FIELDS = [
11  'what',
12  'why',
13  'fix',
14  'currentBehavior',
15  'desiredBehavior',
16  'verify',
17];
18
19const BAD_INVOCATION_CLAIM =
20  /\bfunction invocations?\b[^.!?\n]{0,120}\b(?:drop|drops|fall|falls|decrease|decreases|decline|declines|reduce|reduces|reduced|cut|cuts)\b[^.!?\n]*(?:[.!?]|$)|\b
21
22const SAFE_REPLACEMENT =
23  '95th percentile duration should drop; function invocation count may stay flat unless a separate CDN or static-rendering change is made.';
24
25export function apply(rec) {
26  if (!String(rec?.candidateRef ?? '').startsWith('slow_route:')) return {};
27  const tags = [];
28  for (const field of STRING_FIELDS) {
29    if (typeof rec?.[field] !== 'string') continue;
30    const before = rec[field];
31    const after = before.replace(BAD_INVOCATION_CLAIM, SAFE_REPLACEMENT);
32    if (after !== before) {
33      rec[field] = after;
34      tags.push(`function-duration-invocations:${field}`);
35    }
36  }
37  return tags.length > 0 ? { tags } : {};
38}