9.0.0 / 2021-06-07

💥 Breaking Changes

• #4633: Drop Node.js v10.x support (@juergba)

• #4635: import-first loading of test files (@giltayar)

Mocha is going ESM-first! This means that it will now use ESM import(test_file) to load the test files, instead of the CommonJS require(test_file). This is not a problem, as import can also load most files that require does. In the rare cases where this fails, it will fallback to require(...). This ESM-first approach is the next step in Mocha's ESM migration, and allows ESM loaders to load and transform the test file.

• #4636: Remove deprecated utils.lookupFiles() (@juergba)

• #4638: Limit the size of actual/expected for diff generation (@juergba)

• #4389: Refactoring: Consuming log-symbols alternate to code for win32 in reporters/base (@MoonSupport)

🎉 Enhancements

• #4640: Add new option --dry-run (@juergba)

🐛 Fixes

• #4128: Fix: control stringification of error message (@syeutyu)

🔩 Other

• #4646: Deprecate Runner(suite: Suite, delay: boolean) signature (@juergba)
• #4643: Update production dependencies (@juergba)