Updated Number().toFixed() polyfill to add-then-remove the trailing '1' in every case.

Number.toFixed.js

// 14 March 2019
// Updated Number().toFixed() polyfill to add-then-remove the trailing '1' in every case.
// see original at https://gist.github.com/dfkaye/e977af36e668aa134c0ce55bab5bb15f
// and at https://dfkaye.wordpress.com/2017/12/06/number-tofixed-rounding-errors-broken-but-fixable/

/*
// fixes blog post solution

;(1.005).toFixed(2) == "1.01" || (function(prototype) {
  var toFixed = prototype.toFixed
  prototype.toFixed = function(fractionDigits) {
    var s = String(this)
    var n = ~s.indexOf('.') ? s : s + '1'
    
    return toFixed.call(+n, fractionDigits).slice(0, -1);
  }
}(Number.prototype));
*/

/*
// alternate fix found on stackoverflow
// see https://stackoverflow.com/questions/10015027/javascript-tofixed-not-rounding/48356552#48356552

;(1.005).toFixed(2) == "1.01" || (function(prototype) {
  var toFixed = prototype.toFixed

  prototype.toFixed = function(fractionDigits) {
    return this.toLocaleString(0, {
      minimumFractionDigits: fractionDigits,
      maximumFractionDigits: fractionDigits
    })
  }

}(Number.prototype));
*/

// run the rest of this to see results in console...

function test({fraction, size}) {

  // Happy side-effect: `toString()` removes trailing zeroes.
  var f = fraction.toString()
  var fixed = f.split('.')[1].length - 1
  
  // All this to create the expectedFraction message...
  var last = Number(f.charAt(f.length - 1))
  var digit = Number(f.charAt(f.length - 2))

  last >= 5 && (digit = digit + 1)

  var expectedFraction = f.replace(/[\d]{2,2}$/, digit)
  
  var map = Array(size).fill(0)
    .map(function(v, i) {
      return i + 1
    })
    .filter(function(v) {
      // Compares 1.015 to 1.0151 b/c fixing by more than one decimal place rounds correctly.
      var n = v + Number(fraction) // number 1.015
      var s = n.toFixed(fixed) // string "1.015"
      var s1 = Number(n + '1').toFixed(fixed) // string "1.0151"
      console.log(s, s1);
      
      return s != s1
    })
    .map(function(v, i) {
      console.log(v)
      return {
        given: (v + Number(fraction)).toString(),
        expected: (Number(v.toFixed(0)) + Number(expectedFraction)).toString(),
        actual: Number(v + fraction).toFixed(fixed)
      }
    });
  
  console.log(map);
  
  return map;
}

test({ fraction: .015, size: 128 }).forEach(function(item) {
  console.log(item)
});

;(function () {
  ;(1.005).toFixed(2) == "1.01" || (function(prototype) {
    var toFixed = prototype.toFixed
    prototype.toFixed = function(fractionDigits) {
      var s = String(this)
      var n = ~s.indexOf('.') ? s : s + '1'

      return toFixed.call(+n, fractionDigits).slice(0, -1);
    }

    /*
    prototype.toFixed = function(fractionDigits) {
      return this.toLocaleString(0, {
        minimumFractionDigits: fractionDigits,
        maximumFractionDigits: fractionDigits
      })
    }*/

  }(Number.prototype));
  
});


console.log(
(1.005).toFixed(2)
)

console.log(
(1.005).toFixed(4)
)

console.log(
(1.0149999).toFixed(2)
)

console.log(
(1.0149999).toFixed(4)
)