Migration 008: add script for removing redundant flags

scripts/migrations/008-remove-redundant-flags.js

@@ -0,0 +1,171 @@
+#!/usr/bin/env node
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/ */
+
+'use strict';
+const fs = require('fs');
+const path = require('path');
+const { platform } = require('os');
+
+const compareVersions = require('compare-versions');
+
+const bcd = require('../..');
+
+/** Determines if the OS is Windows */
+const IS_WINDOWS = platform() === 'win32';
+
+let twoYearsAgo = new Date(Date.now());
+twoYearsAgo.setFullYear(twoYearsAgo.getFullYear() - 2);
+
+const getEarliestVersion = (...args) => {
+  const versions = args
+    .filter(version => typeof version === 'string')
+    .map(version => version.replace('≤', ''));
+
+  let earliestVersion = versions[0];
+
+  for (const version of versions) {
+    if (compareVersions.compare(earliestVersion, version, '>'))
+      earliestVersion = version;
+  }
+
+  return earliestVersion;
+};
+
+const removeRedundantFlags = (key, value) => {
+  if (key === '__compat') {
+    for (const [browser, originalSupportData] of Object.entries(
+      value.support,
+    )) {
+      if (originalSupportData !== undefined) {
+        const supportData = Array.isArray(originalSupportData)
+          ? originalSupportData
+          : [originalSupportData];
+        const result = [];
+
+        const simpleStatement = supportData.find(statement => {
+          const ignoreKeys = new Set([
+            'version_removed',
+            'notes',
+            'partial_implementation',
+          ]);
+          const keys = Object.keys(statement).filter(
+            key => !ignoreKeys.has(key),
+          );
+          return keys.length === 1;
+        });
+
+        for (let i = 0; i < supportData.length; i++) {
+          let addData = true;
+
+          if (supportData[i].flags) {
+            const versionToCheck = getEarliestVersion(
+              supportData[i].version_removed ||
+                (simpleStatement && supportData[i].version_added),
+              simpleStatement && simpleStatement.version_added,
+            );
+
+            if (typeof versionToCheck === 'string') {
+              const releaseDate = new Date(
+                bcd.browsers[browser].releases[
+                  versionToCheck.replace('≤', '')
+                ].release_date,
+              );
+
+              if (releaseDate <= twoYearsAgo) {
+                addData = false;
+              }
+            }
+          }
+
+          if (addData) result.push(supportData[i]);
+        }
+
+        if (result.length == 0) {
+          if (!simpleStatement) {
+            value.support[browser] = { version_added: false };
+          } else {
+            continue;
+          }
+        } else if (result.length == 1) {
+          value.support[browser] = result[0];
+        } else {
+          value.support[browser] = result;
+        }
+      }
+    }
+  }
+  return value;
+};
+
+/**
+ * @param {Promise<void>} filename
+ */
+const fixRedundantFlags = filename => {
+  const actual = fs.readFileSync(filename, 'utf-8').trim();
+  const expected = JSON.stringify(
+    JSON.parse(actual, removeRedundantFlags),
+    null,
+    2,
+  );
+
+  if (IS_WINDOWS) {
+    // prevent false positives from git.core.autocrlf on Windows
+    actual = actual.replace(/\r/g, '');
+    expected = expected.replace(/\r/g, '');
+  }
+
+  if (actual !== expected) {
+    fs.writeFileSync(filename, expected + '\n', 'utf-8');
+  }
+};
+
+if (require.main === module) {
+  /**
+   * @param {string[]} files
+   */
+  function load(...files) {
+    for (let file of files) {
+      if (file.indexOf(__dirname) !== 0) {
+        file = path.resolve(__dirname, '..', '..', file);
+      }
+
+      if (!fs.existsSync(file)) {
+        continue; // Ignore non-existent files
+      }
+
+      if (fs.statSync(file).isFile()) {
+        if (path.extname(file) === '.json') {
+          fixRedundantFlags(file);
+        }
+
+        continue;
+      }
+
+      const subFiles = fs.readdirSync(file).map(subfile => {
+        return path.join(file, subfile);
+      });
+
+      load(...subFiles);
+    }
+  }
+
+  if (process.argv[2]) {
+    load(process.argv[2]);
+  } else {
+    load(
+      'api',
+      'css',
+      'html',
+      'http',
+      'svg',
+      'javascript',
+      'mathml',
+      'test',
+      'webdriver',
+      'webextensions',
+    );
+  }
+}
+
+module.exports = { removeRedundantFlags, fixRedundantFlags };