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javascriptmomentjstampermonkey

Convert Text to Integer in JS

I am trying to use Tampermonkey to find a UTC time offset and return it as as a time. The website shows an offset which I pull here 

waitForKeyElements (".UTCText", getTZ_Offset);

which returns a string 

console.log ("Found timezone offset: ", tzOffset);

usually like this 08:00 It can be + or -

Then i want to convert that into actual time. Eg if UTC time is 00:00, I would like to print a string "The users time is 08:00" if the offset was +08:00.

I thought i could use momentjs to get UTC time moment().utcOffset(tzOffset) and pass the offset.

When i do that it just returns NaN

What am I doing wrong?

Solution

  • Multiply the part before the : by 60, and add it to the second part:

    const tzOffset = '08:00';
const [hourOffset, minuteOffset] = tzOffset.split(':').map(Number);

const totalMinuteOffset = hourOffset * 60 + minuteOffset;
console.log(totalMinuteOffset);

    If the input may be negative, then check that as well:

    const tzOffset = '-08:00';
const [_, neg, hourOffset, minuteOffset] = tzOffset.match(/(-)?(\d{2}):(\d{2})/);

const totalMinuteOffset = (neg ? -1 : 1) * (hourOffset * 60 + Number(minuteOffset));
console.log(totalMinuteOffset);

    A few time zones differ from UTC not only by hours, but by minutes as well (eg, UTC +5:30, UTC +9:30), so just parseInt, even if it worked, wouldn't be reliable everywhere.