Get a list of valid time zones in Go

Question

I\'d like to write a method that will populate a Go Language array with the common timezones that are accepted by the time.Format() call, for use in an HTML tem

Answer 1

Here is an example: https://play.golang.org/p/KFGQiW5A1P-

package main

import (
    "fmt"
    "io/ioutil"
    "strings"
    "unicode"
)

func main() {
    fmt.Println(GetOsTimeZones())
}

func GetOsTimeZones() []string {
    var zones []string
    var zoneDirs = []string{
        // Update path according to your OS
        "/usr/share/zoneinfo/",
        "/usr/share/lib/zoneinfo/",
        "/usr/lib/locale/TZ/",
    }

    for _, zd := range zoneDirs {
        zones = walkTzDir(zd, zones)

        for idx, zone := range zones {
            zones[idx] = strings.ReplaceAll(zone, zd+"/", "")
        }
    }

    return zones
}

func walkTzDir(path string, zones []string) []string {
    fileInfos, err := ioutil.ReadDir(path)
    if err != nil {
        return zones
    }

    isAlpha := func(s string) bool {
        for _, r := range s {
            if !unicode.IsLetter(r) {
                return false
            }
        }
        return true
    }

    for _, info := range fileInfos {
        if info.Name() != strings.ToUpper(info.Name()[:1])+info.Name()[1:] {
            continue
        }

        if !isAlpha(info.Name()[:1]) {
            continue
        }

        newPath := path + "/" + info.Name()

        if info.IsDir() {
            zones = walkTzDir(newPath, zones)
        } else {
            zones = append(zones, newPath)
        }
    }

    return zones
}