• Export local definitions. #118
• Update local definitions. #120
• Fix documentation for the type c character data format. #116
• Upgrade dependencies.

• Update dependencies.
• Make build reproducible.

• Adopt type: module.

This package now requires Node.js 12 or higher. For more, please read Sindre Sorhus’s FAQ.

• Change the default minus sign to the minus sign (−) instead of hyphen-minus (-). #62

This release adopts ES2015 language features such as for-of and drops support for older browsers, including IE. If you need to support pre-ES2015 environments, you should stick with d3-format 1.x or use a transpiler.

• Fix decimal d formatting of numbers greater than or equal to 1e21. #24
• Update dependencies.

• Fix sign of near-zero negative values when using the + sign directive. #92

• Fix trimming of trailing zeroes in exponents. #83
• Declare setting the default locale as a side effect. #84

• Add sideEffects: false to the package.json.

• Include locale files when publishing.

• Add d3.FormatSpecifier.
• Allow minus sign to be localized. Thanks, @benib! #76
• Allow NaN to be localized. #62
• Fix sv-SE’s currency symbol. Thanks, @haf! #73
• Fix type coercion for locales.
• Add en-IE locale. Thanks, @gavinsykes!
• Add es-BO locale. Thanks, @severo!
• Adopt exact paths in imports.
• Use explicit files when publishing.
• Update dependencies.

• Add ~ option to trim insignificant zeros. Thanks, @vasturiano! (#54)
• Fix d3.formatSpecifier to not bake shorthand aliases.

• Fix relative order of the currency suffix and SI prefix (#53).

• Fix thousands separator in fr-FR locale. (#50) Thanks, @victornoel!

• Locales can now override the percent sign suffix. Thanks, @davinov! (#45)

• Locales can now define numeral systems, such as Hindu–Arabic. Thanks, @Ashamandi! (#40)
• Fix formatting of negative infinity. (#42)

• Add module entry point to package.json.

• First stable release.
• Add d3.formatDefaultLocale.
• Locale JSON files are now ASCII-encoded.

Changes since D3 3.x

If a precision is not specified, the formatting behavior has changed: there is now a default precision of 6 for all directives except none, which defaults to 12. In 3.x, if you did not specify a precision, the number was formatted using its shortest unique representation (per number.toString); this could lead to unexpected digits due to floating point math. The new default precision in 4.0 produces more consistent results:

var f = d3.format("e");
f(42);        // "4.200000e+1"
f(0.1 + 0.2); // "3.000000e-1"

To trim insignificant trailing zeroes, use the none directive, which is similar g. For example:

var f = d3.format(".3");
f(0.12345);   // "0.123"
f(0.10000);   // "0.1"
f(0.1 + 0.2); // "0.3"

Under the hood, number formatting has improved accuracy with very large and very small numbers by using number.toExponential rather than Math.log to extract the mantissa and exponent. Negative zero (-0, an IEEE 754 construct) and very small numbers that round to zero are now formatted as unsigned zero. The inherently unsafe d3.round method has been removed, along with d3.requote.

The d3.formatPrefix method has been changed. Rather than returning an SI-prefix string, it returns an SI-prefix format function for a given specifier and reference value. For example, to format thousands:

var f = d3.formatPrefix(",.0", 1e3);
f(1e3); // "1k"
f(1e4); // "10k"
f(1e5); // "100k"
f(1e6); // "1,000k"

Unlike the s format directive, d3.formatPrefix always employs the same SI-prefix, producing consistent results:

var f = d3.format(".0s");
f(1e3); // "1k"
f(1e4); // "10k"
f(1e5); // "100k"
f(1e6); // "1M"

The new ( sign option uses parentheses for negative values. This is particularly useful in conjunction with $. For example:

d3.format("+.0f")(-42);  // "-42"
d3.format("(.0f")(-42);  // "(42)"
d3.format("+$.0f")(-42); // "-$42"
d3.format("($.0f")(-42); // "($42)"

The new = align option places any sign and symbol to the left of any padding:

d3.format(">6d")(-42);  // "   -42"
d3.format("=6d")(-42);  // "-   42"
d3.format(">(6d")(-42); // "  (42)"
d3.format("=(6d")(-42); // "(  42)"

The b, o, d and x directives now round to the nearest integer, rather than returning the empty string for non-integers:

d3.format("b")(41.9); // "101010"
d3.format("o")(41.9); // "52"
d3.format("d")(41.9); // "42"
d3.format("x")(41.9); // "2a"

The c directive is now for character data (i.e., literal strings), not for character codes. The is useful if you just want to apply padding and alignment and don’t care about formatting numbers. For example, the infamous left-pad (as well as center- and right-pad!) can be conveniently implemented as:

d3.format(">10c")("foo"); // "       foo"
d3.format("^10c")("foo"); // "   foo    "
d3.format("<10c")("foo"); // "foo       "

There are several new methods for computing suggested decimal precisions; these are used by d3-scale for tick formatting, and are helpful for implementing custom number formats: d3.precisionFixed, d3.precisionPrefix and d3.precisionRound. There’s also a new d3.formatSpecifier method for parsing, validating and debugging format specifiers; it’s also good for deriving related format specifiers, such as when you want to substitute the precision automatically.

You can now set the default locale using d3.formatDefaultLocale! The locales are published as JSON to NPM.

See CHANGES for all D3 changes since 3.x.

• Export to the global d3 in vanilla environments (d3/d3#2840).
• Define locales as JSON data, not code (#22).

• Prefix exported symbols with “format”.
• Implement format.toString (#17).

• Fix off-by-one in precisionRound.
• Add Czech locale.

• Expose locales as symbols, not strings (#15).

• Defined d3-format module (and d3_format global), not format.

• Fix formatting of negative zero (#14).

• Adjust the package.json definition for npm users.

• Fix decimal separator in ja-JP locale.

• localeFormat now accepts the name of a built-in locale, such as "en-US".

• Fix for IE11 crash in number.toExponential(undefined).