Interface FormatQuantityOptions

If qty is a string, allow trailing invalid characters after the numeric portion.

Output the fraction slash character (⁄) instead of the "solidus" slash (/) for fractions. Results appear like "1⁄2" instead of "1/2". Overridden by the vulgarFractions option.

Output in Roman numerals. Provided value must be between 1 and 3999, inclusive. Decimal values will be ignored (Math.floor is used to remove them). Overrides all other options.

String to place between the whole number and fraction parts. When not specified, defaults to " " for ASCII and fraction-slash fractions, and "" for vulgar fractions (preserving the standard typographic convention of no space before vulgar fraction characters).

Amount by which a number can deviate from the calculated quotient to be considered a match. For example, 0.66 is close enough to 2 ÷ 3 (which is 0.66666... repeating) to be considered equivalent so the function will return "2/3". The smaller this number, the higher the likelihood that the function will return a decimal instead of a fraction or mixed number.

0 means only exact quotients match. false disables fraction matching entirely, so decimal values are always returned as decimals.

Any other value—negative, non-numeric, NaN, null, undefined—resolves to the default.

Output vulgar fractions, like "½" instead of "1/2", when appropriate. Overrides the fractionSlash option.

String to return when the input evaluates numerically to zero.