code-boxx/0-JS-ROUND-OFF.MD

## 0-JS-ROUND-OFF.MD

      
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              0-JS-ROUND-OFF.MD
            
          
    JAVASCRIPT ROUND OFF NUMBER

https://code-boxx.com/javascript-round-up-down-decimal-places/
LICENSE

Copyright by Code Boxx
Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.

  
## 1-round.html
<!DOCTYPE html>
<html>
  <head>
    <title>Javascript Round</title>
    <script>
    // (A) NUMBERS
    var numA = 11.4;
    var numB = 12.5;

    // (B) ROUND OFF
    // < 0.5 - ROUND DOWN
    // >= 0.5 - ROUND UP
    console.log(Math.round(numA)); // 11
    console.log(Math.round(numB)); // 13

    // (C) CEILING - ALWAYS ROUND UP
    console.log(Math.ceil(numA)); // 12
    console.log(Math.ceil(numB)); // 13

    // (D) FLOOR - ALWAYS ROUND DOWN
    console.log(Math.floor(numA)); // 11
    console.log(Math.floor(numB)); // 12

    // (E) TRUNCATE - NO ROUND OFF, JUST DROP DECIMAL PLACES
    console.log(Math.trunc(numA)); // 11
    console.log(Math.trunc(numB)); // 12
    </script>
  </head>
  <body></body>
</html>

## 2-places.html
<!DOCTYPE html>
<html>
  <head>
    <title>Javascript Round</title>
    <script>
    // (A) A BETTER ROUND OFF
    //   NUM : NUMBER TO BE ROUNDED
    //   PLACES : NUMBER OF DECIMAL PLACES
    //   MODE : NONE - ROUND, 0 - FLOOR, 1 - CEILING
    function rounder (num, places, mode) {
      // (A1) MULTIPLIER
      var mult = parseInt("1" + "0".repeat(places));
      num = num * mult;

      // (A2) ROUND OFF
      if (mode === 1) { num = Math.ceil(num); }
      else if (mode === 0) { num = Math.floor(num); }
      else { num = Math.round(num); }

      // (A3) RETURN RESULTS
      return num / mult;
    }

    // (B) TEST
    var num = 1.2374;
    // 2 DECIMALS ROUND - 1.24
    console.log(rounder(num, 2));
    // 3 DECIMALS FLOOR - 1.237
    console.log(rounder(num, 3, 0));
    // 3 DECIMALS CEILING - 1.238
    console.log(rounder(num, 3, 1));
    </script>
  </head>
  <body></body>
</html>
	<!DOCTYPE html>
	<html>
	<head>
	<title>Javascript Round</title>
	<script>
	// (A) NUMBERS
	var numA = 11.4;
	var numB = 12.5;

	// (B) ROUND OFF
	// < 0.5 - ROUND DOWN
	// >= 0.5 - ROUND UP
	console.log(Math.round(numA)); // 11
	console.log(Math.round(numB)); // 13

	// (C) CEILING - ALWAYS ROUND UP
	console.log(Math.ceil(numA)); // 12
	console.log(Math.ceil(numB)); // 13

	// (D) FLOOR - ALWAYS ROUND DOWN
	console.log(Math.floor(numA)); // 11
	console.log(Math.floor(numB)); // 12

	// (E) TRUNCATE - NO ROUND OFF, JUST DROP DECIMAL PLACES
	console.log(Math.trunc(numA)); // 11
	console.log(Math.trunc(numB)); // 12
	</script>
	</head>
	<body></body>
	</html>