test-repo/changelog_unreleased/api/12574.md

[BREAKING] Change public APIs to asynchronous (#12574, #12788, #12790, #13265 by @fisker)

• prettier.format() returns Promise<string>
• prettier.formatWithCursor() returns Promise<{formatted: string, cursorOffset: number}>
• prettier.formatAST() returns Promise<string>
• prettier.check() returns Promise<boolean>
• prettier.getSupportInfo() returns Promise
• prettier.clearConfigCache() returns Promise<void>
• prettier.resolveConfig.sync is removed
• prettier.resolveConfigFile.sync is removed
• prettier.getFileInfo.sync is removed

If you still need sync APIs, you can try @prettier/sync