Internationalization

The Intl object and all its formatters are not available in SSJS, and the toLocaleString / toLocaleUpperCase family ignore locale arguments — they behave as plain, non-localized no-ops. Use AMPscript FormatNumber / FormatDate for real locale formatting.

Verification pending Differs from official docs

The Intl object is not available in SSJS, and the toLocale* methods do not actually localize. The SFMC server-side JavaScript engine (Jint) does not expose the ECMAScript Internationalization API: Intl is undefined, so none of its formatters (Intl.NumberFormat, Intl.DateTimeFormat, Intl.Collator, …) exist. The toLocaleString, toLocaleUpperCase, toLocaleLowerCase, toLocaleDateString, and related methods do exist, but they ignore any locale argument and fall back to a fixed, non-localized representation.

For real locale-aware number and date formatting, use AMPscript’s FormatNumber and FormatDate (callable from SSJS via Platform.Function.FormatNumber / Platform.Function.FormatDate).

Status legend

Icon	Meaning
❌ Missing	Not available (`typeof` is `"undefined"`)
⚠️ No-op	Exists but ignores locale arguments (differs from spec)

Members

Member	ES	Status	Notes
`Intl`	ES2015	❌ Missing	Entire Internationalization API is absent
`Number.prototype.toLocaleString`	ES3	⚠️ No-op	Ignores locale; returns the plain number string
`String.prototype.toLocaleUpperCase`	ES3	⚠️ No-op	Behaves like `toUpperCase()`
`String.prototype.toLocaleLowerCase`	ES3	⚠️ No-op	Behaves like `toLowerCase()`
`Date.prototype.toLocaleDateString`	ES3	⚠️ No-op	Returns a fixed English-format string

Intl

(ES2015) — ❌ Missing. Intl is not defined — typeof Intl === "undefined". None of its formatter constructors (Intl.NumberFormat, Intl.DateTimeFormat, Intl.Collator, Intl.PluralRules, Intl.RelativeTimeFormat, Intl.ListFormat, Intl.Locale, Intl.Segmenter, Intl.DisplayNames) are available.

For locale-aware formatting, use AMPscript from SSJS:

// Locale-aware number formatting (instead of Intl.NumberFormat)
var formatted = Platform.Function.FormatNumber(1234567.89, "N", "de-DE");
Write(formatted); // "1.234.567,89"

toLocaleString family

⚠️ No-op. These methods exist but ignore the locale argument. Runtime-verified behaviour:

// Number.prototype.toLocaleString — ignores the locale, no grouping separators
Write((123456.789).toLocaleString());        // "123456.789"
Write((123456.789).toLocaleString("de-DE")); // "123456.789"  (locale ignored — no "123.456,789")

// String.prototype.toLocaleUpperCase — behaves like toUpperCase()
Write("abc".toLocaleUpperCase());             // "ABC"

// Date.prototype.toLocaleDateString — fixed English format, not locale-aware
var d = new Date(2020, 0, 15);
Write(d.toLocaleDateString());                // "Wed, 15 Jan 2020"

Because the locale argument is silently ignored, do not rely on toLocaleString(locale) to produce grouped numbers, localized month names, or locale-specific date order. Use Platform.Function.FormatNumber / Platform.Function.FormatDate with an explicit culture code instead.