give a value and lookup array, and returns the closest value in the array.

roundbytable.js

var getRoundupValue = function (val, table) {                                                                                                                                                                                                     
  var result;
  if (val <= table[0]) {
    result = table[0];
  }
  else if (val >= table[table.length - 1]) {
    result = table[table.length - 1];
  }
  else {
    var v1, v0, d0, d1;
    loop:for (var i = 1, len = table.length; i < len; ++i) {
      v1 = table[i];
      v0 = table[i - 1];
      if (v1 == val) {
        result = val;
        break loop;
      }
      else if (v1 > val) {
        d1 = v1 - val;
        d0 = val - v0;
        if (d1 < d0) {
          result = v1;
        }
        else {
          result = v0
        }
        break loop;
      }
    }
  }
  return result;
};