locale.format()

locale.format(specifier)

Returns a new formatter for the given string specifier. The specifier string may contain the following directives:

• %a - abbreviated weekday name.*
• %A - full weekday name.*
• %b - abbreviated month name.*
• %B - full month name.*
• %c - the locale’s date and time, such as %x, %X.*
• %d - zero-padded day of the month as a decimal number [01,31].
• %e - space-padded day of the month as a decimal number [ 1,31]; equivalent to %_d.
• %H - hour (24-hour clock) as a decimal number [00,23].
• %I - hour (12-hour clock) as a decimal number [01,12].
• %j - day of the year as a decimal number [001,366].
• %m - month as a decimal number [01,12].
• %M - minute as a decimal number [00,59].
• %L - milliseconds as a decimal number [000, 999].
• %p - either AM or PM.*
• %S - second as a decimal number [00,61].
• %U - Sunday-based week of the year as a decimal number [00,53].
• %w - Sunday-based weekday as a decimal number [0,6].
• %W - Monday-based week of the year as a decimal number [00,53].
• %x - the locale’s date, such as %-m/%-d/%Y.*
• %X - the locale’s time, such as %-I:%M:%S %p.*
• %y - year without century as a decimal number [00,99].
• %Y - year with century as a decimal number.
• %Z - time zone offset, such as -0700, -07:00, -07, or Z.
• %% - a literal percent sign (%).

Directives marked with an asterisk (*) may be affected by the locale definition.

For %U, all days in a new year preceding the first Sunday are considered to be in week 0. For %W, all days in a new year preceding the first Monday are considered to be in week 0. Week numbers are computed using interval.count. For example, 2015-52 and 2016-00 represent Monday, December 28, 2015, while 2015-53 and 2016-01 represent Monday, January 4, 2016. This differs from the ISO week date, which uses a more complicated definition!

The % sign indicating a directive may be immediately followed by a padding modifier:

• 0 - zero-padding
• _ - space-padding
• - - disable padding

If no padding modifier is specified, the default is 0 for all directives except %e, which defaults to _. (In some implementations of strftime and strptime, a directive may include an optional field width or precision; this feature is not yet implemented.)

The returned function formats a specified date, returning the corresponding string.

var formatMonth = d3.timeFormat("%B"),
    formatDay = d3.timeFormat("%A"),
    date = new Date(2014, 4, 1); // Thu May 01 2014 00:00:00 GMT-0700 (PDT)

formatMonth(date); // "May"
formatDay(date); // "Thursday"