prism/dangerfile.js

141 lines
3.6 KiB
JavaScript

const { markdown } = require('danger');
const fs = require('fs').promises;
const gzipSize = require('gzip-size');
const git = require('simple-git').gitP(__dirname);
/**
* Returns the contents of a text file in the base of the PR.
*
* The base is usually PrismJS/prism/master.
*
* @param {string} path
* @returns {Promise<string>}
*/
function readBaseFile(path) {
return fs.readFile(path, 'utf-8');
}
/**
* Returns the contents of a text file in the pull request branch.
*
* @param {string} path
* @returns {Promise<string>}
*/
function readPRFile(path) {
return git.show([`pr:${path}`]);
}
/**
* Returns the relative paths of all files changed in the PR.
*
* @returns {Promise<string[]>}
*/
const getChangedFiles = async () => {
// Determine the merge base between master and the PR branch.
// If files changed in master since PR was branched they would show in the diff otherwise.
// https://stackoverflow.com/questions/25071579/list-all-files-changed-in-a-pull-request-in-git-github
const mergeBase = (await git.raw(['merge-base', 'pr', 'HEAD'])).trim();
const result = await git.diff(['--name-only', '--no-renames', 'pr', mergeBase]);
return (result || '').trim().split(/\r?\n/g);
};
const getChangedMinifiedFiles = async () => {
const changed = await getChangedFiles();
return changed.filter(file => file.endsWith('.min.js'));
};
// https://stackoverflow.com/questions/15900485/correct-way-to-convert-size-in-bytes-to-kb-mb-gb-in-javascript
const formatBytes = (bytes, decimals = 2) => {
if (bytes === 0) {
return '0 Bytes';
}
const k = 1000;
const dm = decimals < 0 ? 0 : decimals;
const sizes = ['B', 'KB', 'MB', 'GB', 'TB', 'PB', 'EB', 'ZB', 'YB'];
const i = Math.floor(Math.log(Math.abs(bytes)) / Math.log(k));
return parseFloat((bytes / Math.pow(k, i)).toFixed(dm)) + ' ' + sizes[i];
};
const maybePlus = (from, to) => from < to ? '+' : '';
const absDiff = (from, to) => {
if (from === to) {
return formatBytes(0);
}
return `${maybePlus(from, to)}${formatBytes(to - from)}`;
};
const percDiff = (from, to) => {
if (from === to) {
return '0%';
}
return `${maybePlus(from, to)}${(100 * (to - from) / (from || to)).toFixed(1)}%`;
};
const getSummary = (rows, totalMasterFileSize, totalFileSize) => {
const numFiles = rows.length;
const maybeS = rows.length > 0 ? 's' : '';
const byteDiff = absDiff(totalMasterFileSize, totalFileSize);
const percentDiff = percDiff(totalMasterFileSize, totalFileSize);
return `A total of ${numFiles} file${maybeS} have changed, with a combined diff of ${byteDiff} (${percentDiff}).`;
};
const run = async () => {
const minified = await getChangedMinifiedFiles();
if (minified.length === 0) {
markdown(`## No JS Changes`);
return;
}
const rows = [];
let totalFileSize = 0;
let totalMasterFileSize = 0;
for (const file of minified) {
const [fileContents, fileMasterContents] = await Promise.all([
readPRFile(file).catch(() => ''),
readBaseFile(file).catch(() => ''),
]);
const [fileSize, fileMasterSize] = await Promise.all([
gzipSize(fileContents),
gzipSize(fileMasterContents),
]);
totalFileSize += fileSize;
totalMasterFileSize += fileMasterSize;
rows.push([
file,
formatBytes(fileMasterSize),
formatBytes(fileSize),
absDiff(fileMasterSize, fileSize),
percDiff(fileMasterSize, fileSize),
]);
}
markdown(`## JS File Size Changes (gzipped)
${getSummary(rows, totalMasterFileSize, totalFileSize)}
<details>
| file | master | pull | size diff | % diff |
| --- | --- | --- | --- | --- |
${rows.map(row => `| ${row.join(' | ')} |`).join('\n')}
</details>
`);
};
run().catch(err => {
console.error(err);
process.exit(1);
});