Add milli seconds as available unit

Author: hmoragrega

README.md

@@ -29,6 +29,7 @@ nowAgain, err := parser.Since(inTenMinutes, "-10 minutes")
 
 ## Available units
 The available time units are
+* `ms`, `millisecond` or `milliseconds`
 * `s`, `second` or `seconds`
 * `m`, `minute` or `minutes`
 * `h`, `hour`   or `hours`
@@ -44,7 +45,7 @@ It's the number that will multiply the time unit:
 ### Validation
 You can use this regular expression to validate your inputs:
  ```
- ^((\\+|\\-))?([1-9][0-9]*)\\s?(s|seconds?|m|minutes?|h|hours?|d|days?|w|weeks?)$
+ ^((\+|\-))?([1-9][0-9]*)\s?(ms|milliseconds?|s|seconds?|m|minutes?|h|hours?|d|days?|w|weeks?)$
  ```
 
 ## Scope

parser.go

@@ -8,12 +8,33 @@ import (
 )
 
 const (
-	Regex = "^((\\+|\\-))?([1-9][0-9]*)\\s?(s|seconds?|m|minutes?|h|hours?|d|days?|w|weeks?)$"
+	Regex = "^((\\+|\\-))?([1-9][0-9]*)\\s?(ms|milliseconds?|s|seconds?|m|minutes?|h|hours?|d|days?|w|weeks?)$"
 	Day   = time.Hour * 24
 	Week  = Day * 7
 )
 
-var compiledRegex *regexp.Regexp 
+var compiledRegex *regexp.Regexp
+
+var unitMap = map[string]time.Duration{
+	"ms":           time.Millisecond,
+	"millisecond":  time.Millisecond,
+	"milliseconds": time.Millisecond,
+	"s":            time.Second,
+	"second":       time.Second,
+	"seconds":      time.Second,
+	"m":            time.Minute,
+	"minute":       time.Minute,
+	"minutes":      time.Minute,
+	"h":            time.Hour,
+	"hour":         time.Hour,
+	"hours":        time.Hour,
+	"d":            Day,
+	"day":          Day,
+	"days":         Day,
+	"w":            Week,
+	"week":         Week,
+	"weeks":        Week,
+}
 
 // Parser is the service that will provide the package functionality
 type Parser struct {}
@@ -28,6 +49,7 @@ func New() *Parser {
 // The input string must contain a time unit and a signed multiplier ('+' sign by default if omitted)
 //
 // The accepted time unit are:
+//  - `ms`, `millisecond` or `milliseconds`
 //  - `s`, `second` or `seconds`
 //  - `m`, `minute` or `minutes`
 //  - `h`, `hour`   or `hours`
@@ -94,20 +116,12 @@ func (p *Parser) getMultiplier(sign string, multiplier string) (time.Duration, e
 }
 
 func (p *Parser) getDuration(unit string, multiplier time.Duration) (time.Duration, error) {
-	switch unit[:1] {
-	case "s":
-		return time.Second * multiplier, nil
-	case "m":
-		return time.Minute * multiplier, nil
-	case "h":
-		return time.Hour * multiplier, nil
-	case "d":
-		return Day * multiplier, nil
-	case "w":
-		return Week * multiplier, nil
+	duration, found := unitMap[unit]
+	if !found {
+		return 0, fmt.Errorf("The duration unit '%s' is not supported", unit)
 	}
 
-	return 0, fmt.Errorf("The duration unit '%s' is not supported", unit)
+	return duration * multiplier, nil
 }
 
 func (p *Parser) getRegex() (*regexp.Regexp, error) {

parser_test.go

@@ -10,21 +10,24 @@ func TestItParsePositiveDurationsCorrectly(t *testing.T) {
 	parser := after.New()
 
 	valid := map[string]time.Duration{
-		"1s":          time.Second,
-		"+1 second":   time.Second,
-		"20seconds":   time.Second * 20,
-		"1m":          time.Minute,
-		"+1 minute":   time.Minute,
-		"20 minutes":  time.Minute * 20,
-		"1h":          time.Hour,
-		"+1 hour":     time.Hour,
-		"20hours":     time.Hour * 20,
-		"1d":          time.Hour * 24,
-		"+1 day":      time.Hour * 24,
-		"20 days":     time.Hour * 24 * 20,
-		"1w":          time.Hour * 24 * 7,
-		"+1 week":     time.Hour * 24 * 7,
-		"20 weeks":    time.Hour * 24 * 7 * 20,
+		"1 millisecond":   time.Millisecond,
+		"+1ms":            time.Millisecond,
+		"20 milliseconds": time.Millisecond * 20,
+		"1s":              time.Second,
+		"+1 second":       time.Second,
+		"20seconds":       time.Second * 20,
+		"1m":              time.Minute,
+		"+1 minute":       time.Minute,
+		"20 minutes":      time.Minute * 20,
+		"1h":              time.Hour,
+		"+1 hour":         time.Hour,
+		"20hours":         time.Hour * 20,
+		"1d":              time.Hour * 24,
+		"+1 day":          time.Hour * 24,
+		"20 days":         time.Hour * 24 * 20,
+		"1w":              time.Hour * 24 * 7,
+		"+1 week":         time.Hour * 24 * 7,
+		"20 weeks":        time.Hour * 24 * 7 * 20,
 	}
 
 	for input, expected := range valid {
@@ -43,21 +46,24 @@ func TestItParseNegativeDurationsCorrectly(t *testing.T) {
 	parser := after.New()
 
 	valid := map[string]time.Duration{
-		"-1s":         -time.Second,
-		"-1 second":   -time.Second,
-		"-20seconds":  -time.Second * 20,
-		"-1m":         -time.Minute,
-		"-1 minute":   -time.Minute,
-		"-20 minutes": -time.Minute * 20,
-		"-1h":         -time.Hour,
-		"-1 hour":     -time.Hour,
-		"-20hours":    -time.Hour * 20,
-		"-1d":         -time.Hour * 24,
-		"-1 day":      -time.Hour * 24,
-		"-20 days":    -time.Hour * 24 * 20,
-		"-1w":         -time.Hour * 24 * 7,
-		"-1 week":     -time.Hour * 24 * 7,
-		"-20 weeks":   -time.Hour * 24 * 7 * 20,
+		"-1ms":           -time.Millisecond,
+		"-1 millisecond": -time.Millisecond,
+		"-20millisecond": -time.Millisecond * 20,
+		"-1s":            -time.Second,
+		"-1 second":      -time.Second,
+		"-20seconds":     -time.Second * 20,
+		"-1m":            -time.Minute,
+		"-1 minute":      -time.Minute,
+		"-20 minutes":    -time.Minute * 20,
+		"-1h":            -time.Hour,
+		"-1 hour":        -time.Hour,
+		"-20hours":       -time.Hour * 20,
+		"-1d":            -time.Hour * 24,
+		"-1 day":         -time.Hour * 24,
+		"-20 days":       -time.Hour * 24 * 20,
+		"-1w":            -time.Hour * 24 * 7,
+		"-1 week":        -time.Hour * 24 * 7,
+		"-20 weeks":      -time.Hour * 24 * 7 * 20,
 	}
 
 	for input, expected := range valid {