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Merged
mathiasbynens merged 3 commits into from
Sep 23, 2026
Merged

Improve build performance #108

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4e4e669
perf: only write changed files
JLHwung Sep 23, 2026
09ded3d
perf: reduce cluster amount
JLHwung Sep 23, 2026
144ab1b
Update scripts/utils.mjs
JLHwung Sep 23, 2026
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4 changes: 2 additions & 2 deletions scripts/generate-data.mjs
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Original file line number Diff line number Diff line change
@@ -1,11 +1,11 @@
import cluster from 'node:cluster';
import os from 'node:os';
import { availableParallelism } from 'node:os';
import resources from '../data/resources.mjs';
import generateData from '../index.mjs';

// -----------------------------------------------------------------------------

const numCPUs = os.cpus().length;
const numCPUs = Math.min(4, availableParallelism());

const pad = (number) => {
return String(number).padStart(2, '0');
Expand Down
41 changes: 27 additions & 14 deletions scripts/utils.mjs
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Original file line number Diff line number Diff line change
Expand Up @@ -76,6 +76,19 @@ const samePropertyRuns = (codePointProperties) => {
return result;
};

// Only write the file if its content has changed.
// Reading files is cheaper than writing files, and most files don’t change between builds.
const writeFileIfChanged = (filePath, content) => {
try {
if (fs.readFileSync(filePath, 'utf8') === content) {
return;
}
} catch {
// Ignore errors such ENOENT (file not found)
}
fs.writeFileSync(filePath, content);
};

const writeFiles = (options) => {
const version = options.version;
const subType = options.subType;
Expand Down Expand Up @@ -147,11 +160,11 @@ const writeFiles = (options) => {
if (type === 'Sequence_Property' || isNameAliases) {
const sequences = codePoints;
const output = `import { gunzipSync } from 'node:zlib';\n\nexport default ${ gzipInline(sequences) };\n`;
fs.writeFileSync(
writeFileIfChanged(
path.resolve(dir, 'index.mjs'),
output
);
fs.writeFileSync(
writeFileIfChanged(
path.resolve(dir, 'index.d.mts'),
type === 'Sequence_Property'
? `declare const data: string[];\nexport default data;\n`
Expand All @@ -167,19 +180,19 @@ const writeFiles = (options) => {
let symbolsType = 'string[]';
if (!isCaseFoldingOrMapping) {
const encodedRanges = codePoints instanceof regenerate ? encodeRegenerate(codePoints) : encodeRanges(codePoints);
fs.writeFileSync(
writeFileIfChanged(
path.resolve(dir, 'ranges.mjs'),
`import decodeRanges from '../../decode-ranges.mjs';\n\nexport default decodeRanges('${encodedRanges}');\n`
);
fs.writeFileSync(
writeFileIfChanged(
path.resolve(dir, 'ranges.d.mts'),
'import type { UnicodeRange } from "../../decode-ranges.mjs";\n\ndeclare const ranges: UnicodeRange[];\nexport default ranges;\n'
);
fs.writeFileSync(
writeFileIfChanged(
path.resolve(dir, 'regex.mjs'),
'export default /' + regenerate(codePoints).toString() + '/;\n'
);
fs.writeFileSync(
writeFileIfChanged(
path.resolve(dir, 'regex.d.mts'),
'declare const regex: RegExp;\nexport default regex;\n'
);
Expand Down Expand Up @@ -213,19 +226,19 @@ const writeFiles = (options) => {
}
symbolsType = 'Map<string, string>';
}
fs.writeFileSync(
writeFileIfChanged(
path.resolve(dir, 'code-points.mjs'),
codePointsFileContent
);
fs.writeFileSync(
writeFileIfChanged(
path.resolve(dir, 'code-points.d.mts'),
`declare const codePoints: ${ codePointsType };\nexport default codePoints;\n`
);
fs.writeFileSync(
writeFileIfChanged(
path.resolve(dir, 'symbols.mjs'),
symbolsFileContent
);
fs.writeFileSync(
writeFileIfChanged(
path.resolve(dir, 'symbols.d.mts'),
`declare const symbols: ${ symbolsType };\nexport default symbols;\n`
);
Expand All @@ -249,11 +262,11 @@ const writeFiles = (options) => {
JSON.stringify(bidiMirroringGlyphFlatPairs)
}.map((v, i, a) => pair(i & 1, a[i ^ 1], v)));\n`
].join('\n');
fs.writeFileSync(
writeFileIfChanged(
path.resolve(dir, 'index.mjs'),
output
);
fs.writeFileSync(
writeFileIfChanged(
path.resolve(dir, 'index.d.mts'),
`declare const data: Map<number, string>;\nexport default data;\n`
);
Expand All @@ -275,8 +288,8 @@ const writeFiles = (options) => {
const output = `import { gunzipSync } from 'node:zlib';\nimport decodePropertyMap from '../decode-property-map.mjs';\n\nexport default decodePropertyMap(${gzipInline(
flatRuns
)});\n`;
fs.writeFileSync(path.resolve(dir, 'index.mjs'), output);
fs.writeFileSync(path.resolve(dir, 'index.d.mts'), `declare const map: Map<number, string>;\nexport default map;\n`);
writeFileIfChanged(path.resolve(dir, 'index.mjs'), output);
writeFileIfChanged(path.resolve(dir, 'index.d.mts'), `declare const map: Map<number, string>;\nexport default map;\n`);
}
}
return dirMap;
Expand Down
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