casing_dump.mjs RawHistoryFolder

1// SPDX-License-Identifier: MIT
2//
3// Dumps the JavaScript toUpperCase/toLowerCase mapping of every code point
4// whose mapping is not the identity, as JSON on stdout. It is the input of
5// casing.go, which turns it into ../casing_tables.go:
6//
7//   go generate ./expr      (runs: node gen/casing_dump.mjs | go run gen/casing.go -o casing_tables.go)
8//
9// The mapping is that of the JavaScript engine running the script (Node/V8),
10// which is what @actions/expressions uses for case-insensitive comparisons.
11const upper = {};
12const lower = {};
13for (let cp = 0; cp <= 0x10ffff; cp++) {
14  if (cp >= 0xd800 && cp <= 0xdfff) continue;
15  const s = String.fromCodePoint(cp);
16  const u = s.toUpperCase();
17  const l = s.toLowerCase();
18  if (u !== s) upper[cp] = u;
19  if (l !== s) lower[cp] = l;
20}
21process.stdout.write(JSON.stringify({ upper, lower }));