1# i18n<a name="EN-US_TOPIC_0000001101364976"></a> 2 3- [Introduction](#section11660541593) 4- [Directory Structure](#section1464106163817) 5- [Constraints](#section1718733212019) 6- [Usage](#section894511013511) 7- [Repositories Involved](#section15583142420413) 8 9## Introduction<a name="section11660541593"></a> 10 11The i18n module provides a wide array of internationalization \(i18n\) APIs for implementing functions such as date and time formatting. 12 13## Directory Structure<a name="section1464106163817"></a> 14 15The directory structure for the i18n module is as follows: 16 17``` 18/base/global/ 19├── i18n # Code repository for the i18n framework 20│ ├── frameworks # Core code of the i18n framework 21│ ├── interfaces # APIs 22│ │ ├── js # JavaScript APIs 23│ │ └── native # Native APIs 24``` 25 26## Constraints<a name="section1718733212019"></a> 27 28**Development language**: JavaScript 29 30**Language, script, and country codes**: The supported language must be represented by a two- or three-letter code defined in the ISO 639 standard; the supported script must be represented by a four-letter code defined in the ISO 15924 standard; the supported country must be represented by a two-letter code defined in the ISO 3166 standard. 31 32## Usage<a name="section894511013511"></a> 33 34Change the date and time formats \(such as the sequence of year, month, and day, month and week names, and 12-hour or 24-hour system\) following the system settings to adapt to the cultural habits of users in different locales. For details, see the API reference. The sample code is as follows: 35 36``` 37const date = new Date(2021, 11, 17, 3, 24, 0); // Create a Date object containing date and time information. 38fmt = new Intl.DateTimeFormat('en-US') // Create a DateTimeFormat instance. 39console.log(fmt.format(date)); // Format the date and time by using the DateTimeFormat instance. 40``` 41 42## Repositories Involved<a name="section15583142420413"></a> 43 44Globalization subsystem 45 46**global\_i18n\_standard** 47 48global\_resmgr\_standard 49 50