strf()

(format: string | { toString(): string; }, ...values: any[]): I18nString

Returns an I18nString that encapsulates a translated and formatted string, incorporating given values. Before formatting, the format string is automatically translated using the I18nService.getText() method of the currently registered I18n service, if any.

Placeholders in the format string are compatible with C-style sprintf, e.g. %s, %+8i, %.5f, etc. as well as the following custom placeholders:

• ***{comments}*** which are removed

• #{a/b}, #{a/b/c} to select an option based on the numeric value of the first value in the parameter list, for pluralization (e.g. strf("%i file#{/s}", n))

• #n${a/b}, #n${a/b/c} to select an option based on the numeric value of the parameter at position n (1-based index), for pluralization (e.g. strf("User %s has %i message#2${/s}", userName, nMessages))

• %n (non-standard) general-purpose number format, never results in exponential notation

• %{_} to insert nothing at all (blank string)

• %{uc}, %{lc}` for uppercase and lowercase strings

• %{?} for true or false (boolean) and %{!} for negation

• %{n} or %{num} for values cast to Number

• %{then:a:b} to select strings a or b based on boolean value

• %{else:b} to select string b if the value is not boolean true

• %{local:...} for I18n-formatted values; the type part(s) are variable, and will need to be implemented by the I18nService.format method of the currently registered I18n service, e.g. strf("%{local:date}", new Date()).

Note: Asterisks (*) anywhere in a placeholder are replaced by the next value in the parameter list (before the value being represented itself), e.g. in strf("%.*f", precision, number) and strf("%{local:currency:*}", currency, number).

Note: Floating point numbers are formatted using the decimal separator specified by the I18nService.decimalSeparator property of the currently registered I18n service, if any. Number grouping separators are not supported, and if necessary numbers will need to be formatted using %{local:…}.

Note: Use position specifiers (i.e. n$) to change the order of parameters used, e.g. strf("A is %i and B is %i, so %1$i + %2$i equals %i", i1, i2, i1 + i2). This is also helpful for translations where the position of words or numbers must be reversed.