Do you want to add more template.substitution like {{yesterday}} ?

[fcarvalhopacheco]

On your obsidian.lua configuration:

    -- Optional, for templates (see below).
    templates = {
      subdir = 'Templates',
      date_format = '%Y-%m-%d',
      time_format = '%H:%M',
      -- A map for custom variables, the key should be the variable and the value a function
      substitutions = {
        time24 = function()
          return os.date '%H:%M:%S'
        end,
        time12 = function()
          -- Conversion to 12-hour format with AM/PM
          local hour = tonumber(os.date '%H')
          local ampm = hour >= 12 and 'PM' or 'AM'
          hour = hour % 12
          hour = hour == 0 and 12 or hour
          return string.format('%02d:%s %s', hour, os.date '%M:%S', ampm)
        end,
        year = function()
          return os.date('%Y', os.time())
        end,
        month = function()
          return os.date('%B', os.time())
        end,
        yesterday = function()
          return os.date('%Y-%m-%d', os.time() - 86400)
        end,
        nextday = function()
          return os.date('%Y-%m-%d', os.time() + 86400)
        end,
        hdate = function()
          return os.date '%A, %B %d, %Y'
        end,
        rfc3339 = function()
          return os.date '!%Y-%m-%dT%H:%M:%SZ'
        end,
        week = function()
          return os.date('%V', os.time())
        end,
        isoweek = function()
          return os.date('%G-W%V', os.time())
        end,
        isoprevweek = function()
          local adjustment = -7 * 24 * 60 * 60 -- One week in seconds
          return os.date('%G-W%V', os.time() + adjustment)
        end,
        isonextweek = function()
          local adjustment = 7 * 24 * 60 * 60 -- One week in seconds
          return os.date('%G-W%V', os.time() + adjustment)
        end,
        day_of_month = function()
          return os.date('%d', os.time())
        end,
        month_numeric = function()
          return os.date('%m', os.time())
        end,
        weekday = function()
          return os.date('%A', os.time())
        end,
      },
    },

Below is a detailed table of custom variables available for template substitutions.

Specifier	Expands to	Example
{{time24}}	Current time in 24-hour format	"14:45:00"
{{time12}}	Current time in 12-hour format with AM/PM	"2:45:00 PM"
{{year}}	Current year	"2024"
{{month}}	Month name	"March"
{{yesterday}}	Yesterday’s date in ISO format	"2024-03-05"
{{nextday}}	Tomorrow’s date in ISO format	"2024-03-07"
{{hdate}}	Current date in a human-readable format	"Wednesday, March 6, 2024"
{{rfc3339}}	Current date and time in RFC3339 format	"2024-03-06T14:45:00+00:00"
{{week}}	Week number of the year	"10"
{{isoweek}}	ISO week number of the current week	"2024-W10"
{{isoprevweek}}	ISO week number of the previous week	"2024-W09"
{{isonextweek}}	ISO week number of the next week	"2024-W11"
{{day_of_month}}	Day of the month	"06"
{{month_numeric}}	Month as a numeric value	"03"
{{weekday}}	Name of the weekday	"Wednesday"

Reference: #473