Source file src/time/zoneinfo_js.go

     1	// Copyright 2018 The Go Authors. All rights reserved.
     2	// Use of this source code is governed by a BSD-style
     3	// license that can be found in the LICENSE file.
     4	
     5	// +build js,wasm
     6	
     7	package time
     8	
     9	import (
    10		"runtime"
    11		"syscall/js"
    12	)
    13	
    14	var zoneSources = []string{
    15		"/usr/share/zoneinfo/",
    16		"/usr/share/lib/zoneinfo/",
    17		"/usr/lib/locale/TZ/",
    18		runtime.GOROOT() + "/lib/time/zoneinfo.zip",
    19	}
    20	
    21	func initLocal() {
    22		localLoc.name = "Local"
    23	
    24		z := zone{}
    25		d := js.Global().Get("Date").New()
    26		offset := d.Call("getTimezoneOffset").Int() * -1
    27		z.offset = offset * 60
    28		// According to https://tc39.github.io/ecma262/#sec-timezoneestring,
    29		// the timezone name from (new Date()).toTimeString() is an implementation-dependent
    30		// result, and in Google Chrome, it gives the fully expanded name rather than
    31		// the abbreviation.
    32		// Hence, we construct the name from the offset.
    33		z.name = "UTC"
    34		if offset < 0 {
    35			z.name += "-"
    36			offset *= -1
    37		} else {
    38			z.name += "+"
    39		}
    40		z.name += itoa(offset / 60)
    41		min := offset % 60
    42		if min != 0 {
    43			z.name += ":" + itoa(min)
    44		}
    45		localLoc.zone = []zone{z}
    46	}
    47	
    48	// itoa is like strconv.Itoa but only works for values of i in range [0,99].
    49	// It panics if i is out of range.
    50	func itoa(i int) string {
    51		if i < 10 {
    52			return digits[i : i+1]
    53		}
    54		return smallsString[i*2 : i*2+2]
    55	}
    56	
    57	const smallsString = "00010203040506070809" +
    58		"10111213141516171819" +
    59		"20212223242526272829" +
    60		"30313233343536373839" +
    61		"40414243444546474849" +
    62		"50515253545556575859" +
    63		"60616263646566676869" +
    64		"70717273747576777879" +
    65		"80818283848586878889" +
    66		"90919293949596979899"
    67	const digits = "0123456789"
    68	

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