times.go

Documentation: github.com/dustin/go-humanize

     1  package humanize
     2  
     3  import (
     4  	"fmt"
     5  	"math"
     6  	"sort"
     7  	"time"
     8  )
     9  
    10  // Seconds-based time units
    11  const (
    12  	Day      = 24 * time.Hour
    13  	Week     = 7 * Day
    14  	Month    = 30 * Day
    15  	Year     = 12 * Month
    16  	LongTime = 37 * Year
    17  )
    18  
    19  // Time formats a time into a relative string.
    20  //
    21  // Time(someT) -> "3 weeks ago"
    22  func Time(then time.Time) string {
    23  	return RelTime(then, time.Now(), "ago", "from now")
    24  }
    25  
    26  // A RelTimeMagnitude struct contains a relative time point at which
    27  // the relative format of time will switch to a new format string.  A
    28  // slice of these in ascending order by their "D" field is passed to
    29  // CustomRelTime to format durations.
    30  //
    31  // The Format field is a string that may contain a "%s" which will be
    32  // replaced with the appropriate signed label (e.g. "ago" or "from
    33  // now") and a "%d" that will be replaced by the quantity.
    34  //
    35  // The DivBy field is the amount of time the time difference must be
    36  // divided by in order to display correctly.
    37  //
    38  // e.g. if D is 2*time.Minute and you want to display "%d minutes %s"
    39  // DivBy should be time.Minute so whatever the duration is will be
    40  // expressed in minutes.
    41  type RelTimeMagnitude struct {
    42  	D      time.Duration
    43  	Format string
    44  	DivBy  time.Duration
    45  }
    46  
    47  var defaultMagnitudes = []RelTimeMagnitude{
    48  	{time.Second, "now", time.Second},
    49  	{2 * time.Second, "1 second %s", 1},
    50  	{time.Minute, "%d seconds %s", time.Second},
    51  	{2 * time.Minute, "1 minute %s", 1},
    52  	{time.Hour, "%d minutes %s", time.Minute},
    53  	{2 * time.Hour, "1 hour %s", 1},
    54  	{Day, "%d hours %s", time.Hour},
    55  	{2 * Day, "1 day %s", 1},
    56  	{Week, "%d days %s", Day},
    57  	{2 * Week, "1 week %s", 1},
    58  	{Month, "%d weeks %s", Week},
    59  	{2 * Month, "1 month %s", 1},
    60  	{Year, "%d months %s", Month},
    61  	{18 * Month, "1 year %s", 1},
    62  	{2 * Year, "2 years %s", 1},
    63  	{LongTime, "%d years %s", Year},
    64  	{math.MaxInt64, "a long while %s", 1},
    65  }
    66  
    67  // RelTime formats a time into a relative string.
    68  //
    69  // It takes two times and two labels.  In addition to the generic time
    70  // delta string (e.g. 5 minutes), the labels are used applied so that
    71  // the label corresponding to the smaller time is applied.
    72  //
    73  // RelTime(timeInPast, timeInFuture, "earlier", "later") -> "3 weeks earlier"
    74  func RelTime(a, b time.Time, albl, blbl string) string {
    75  	return CustomRelTime(a, b, albl, blbl, defaultMagnitudes)
    76  }
    77  
    78  // CustomRelTime formats a time into a relative string.
    79  //
    80  // It takes two times two labels and a table of relative time formats.
    81  // In addition to the generic time delta string (e.g. 5 minutes), the
    82  // labels are used applied so that the label corresponding to the
    83  // smaller time is applied.
    84  func CustomRelTime(a, b time.Time, albl, blbl string, magnitudes []RelTimeMagnitude) string {
    85  	lbl := albl
    86  	diff := b.Sub(a)
    87  
    88  	if a.After(b) {
    89  		lbl = blbl
    90  		diff = a.Sub(b)
    91  	}
    92  
    93  	n := sort.Search(len(magnitudes), func(i int) bool {
    94  		return magnitudes[i].D > diff
    95  	})
    96  
    97  	if n >= len(magnitudes) {
    98  		n = len(magnitudes) - 1
    99  	}
   100  	mag := magnitudes[n]
   101  	args := []interface{}{}
   102  	escaped := false
   103  	for _, ch := range mag.Format {
   104  		if escaped {
   105  			switch ch {
   106  			case 's':
   107  				args = append(args, lbl)
   108  			case 'd':
   109  				args = append(args, diff/mag.DivBy)
   110  			}
   111  			escaped = false
   112  		} else {
   113  			escaped = ch == '%'
   114  		}
   115  	}
   116  	return fmt.Sprintf(mag.Format, args...)
   117  }
   118
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