How to convert a moment object into a duration in seconds? - momentjs

Question

I found lots of info on converting a duration object into various formats but it's harder to find info on converting a moment object into a duration in seconds.
This answer offers the following solution: myVar = moment.duration(myVar).asSeconds()
However it doesn't work in my case, myVar is in MM:SS format not HH:MM:SS format so I'm getting an aberrant result. Any idea how to adapt it to my situation?
EDIT: here's some code
this.totalTimeSimulation = moment(lastActionEndTime, 'mm:ss').add(additionalTimeDuration, 'seconds').format('mm:ss')
this.totalTimeSimulationInSeconds = moment.duration(this.totalTimeSimulation).asSeconds()
console.log(this.totalTimeSimulation)
console.log(this.totalTimeSimulationInSeconds)
In console I see:
04:00
14400
Should be:
04:00
240
Because 4 minutes equals 240 seconds, not 14400 seconds. Moment.js thinks I'm giving it a duration in HH:MM:SS format when actually I'm giving it in MM:SS format.

Answer 1

Moment threats input like 04:00 as HH:MM
The format is an hour, minute, second string separated by colons like 23:59:59. The number of days can be prefixed with a dot separator like so 7.23:59:59. Partial seconds are supported as well 23:59:59.999.
moment.duration('23:59:59');
moment.duration('23:59:59.999');
moment.duration('7.23:59:59.999');
moment.duration('23:59'); // added in 2.3.0
You can prefix your input with 00: or use moment.duration(Object) constructor using minutes and seconds keys:
const totalTimeSimulation = '04:00'
const totalTimeSimulationInSeconds = moment.duration('00:' + totalTimeSimulation).asSeconds()
console.log(totalTimeSimulation)
console.log(totalTimeSimulationInSeconds)
const parts = totalTimeSimulation.split(':')
const seconds = moment.duration({
minutes: parts[0],
seconds: parts[1]}).asSeconds()
console.log(seconds)
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