Table of Contents

• Internationalization Support
  • Options for building Node.js
    • Disable all internationalization features (none)
    • Build with a pre-installed ICU (system-icu)
    • Embed a limited set of ICU data (small-icu)
      • Providing ICU data at runtime
    • Embed the entire ICU (full-icu)
  • Detecting internationalization support

Internationalization Support#

Node.js has many features that make it easier to write internationalized programs. Some of them are:

• Locale-sensitive or Unicode-aware functions in the ECMAScript Language Specification:
  • String.prototype.normalize()
  • String.prototype.toLowerCase()
  • String.prototype.toUpperCase()
• All functionality described in the ECMAScript Internationalization API Specification (aka ECMA-402):
  • Intl object
  • Locale-sensitive methods like String.prototype.localeCompare() and Date.prototype.toLocaleString()
• The WHATWG URL parser's internationalized domain names (IDNs) support
• require('buffer').transcode()
• More accurate REPL line editing
• require('util').TextDecoder
• RegExp Unicode Property Escapes

Node.js (and its underlying V8 engine) uses ICU to implement these features in native C/C++ code. However, some of them require a very large ICU data file in order to support all locales of the world. Because it is expected that most Node.js users will make use of only a small portion of ICU functionality, only a subset of the full ICU data set is provided by Node.js by default. Several options are provided for customizing and expanding the ICU data set either when building or running Node.js.

Options for building Node.js#

To control how ICU is used in Node.js, four configure options are available during compilation. Additional details on how to compile Node.js are documented in BUILDING.md.

• --with-intl=none / --without-intl
• --with-intl=system-icu
• --with-intl=small-icu (default)
• --with-intl=full-icu

An overview of available Node.js and JavaScript features for each configure option: