Background

I need to get the current time in 15 minutes brackets.

Code

let bDebug = 0;
let arrTimeMinute = [0, 15, 30, 45, 60];
let arrTimeHour = [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23];

//Declare array
var arrTimeBlock = [];

function getTimeBlock(arrTime, iCurrent, arrTimeBlock) {

  // set variables value
  var iPrevious = 0;
  var iNext = 0;

  //iterate through time array
  for (const arrayContextValue of arrTime) 
  {

    //when array context value is greater than the current minute 
    //please exit loop
    if (arrayContextValue > iCurrent) 
    {

      //save next value
      iNext = arrayContextValue;

      break;

    };

    // save current array context as previous value
    iPrevious = arrayContextValue;

  };

  //remove previously saved entries
  arrTimeBlock.length = 0;

  //save values
  arrTimeBlock.push(iPrevious);
  arrTimeBlock.push(iNext);

};


//get current date and time
var objTS = new Date();

//get current time ( as string )
var strTime = objTS.getHours() + ":" + objTS.getMinutes() + ":" + objTS.getSeconds();

//get current minute
var iMinuteCurrent = objTS.getMinutes();

//get current hour
var iHourCurrent = objTS.getHours();

//display current time ( as string )
console.log("The current time is " + strTime);

//call time function
getTimeBlock(arrTimeMinute, iMinuteCurrent, arrTimeBlock);

//save function result
timeBlockMinuteBegin = arrTimeBlock[0];
timeBlockMinuteEnd = arrTimeBlock[1];

//call time function
getTimeBlock(arrTimeHour, iHourCurrent, arrTimeBlock);

//save function result
timeBlockHourBegin = arrTimeBlock[0];
timeBlockHourEnd = arrTimeBlock[1];

if (bDebug == 1) 
{
  console.log("");

  console.log("");
}

// Display previous and next time 
console.log("Previous Minute is " + timeBlockMinuteBegin);
console.log("Next Minute is " + timeBlockMinuteEnd);

// Display previous and next hour
console.log("Previous Hour is " + timeBlockHourBegin);
console.log("Next Hour is " + timeBlockHourEnd);

Output

jsfiddle.net

Tools

Online JavaScript Simulation Environment

Upon Googling, discovered jsfiddle.net ( https://jsfiddle.net/ ).

Went with it.

Works a charm.

Code Sharing

Git / Gist

Link