简化的javascript具有几乎相同代码的某些功能

Question

Hei, I'm working an app to simulate prices. I have a code like this.

  function max110(x) {
     if (x >= '1' && x <= '50') {
         var sum = 120 * x;
         hasil.value = 'Rp.' + parseFloat(sum * 1000);
     } else if (x >= '51' && x <= '100') {
         var sum = 115 * x;
         hasil.value = 'Rp.' + parseFloat(sum * 1000);
     } else if (x >= '101' && x <= '200') {
         var sum = 110 * x;
         hasil.value = 'Rp.' + parseFloat(sum * 1000);
     } else {
         hasil.value = 'error!';
     }
 }

 function max115(x) {
     if (x >= '1' && x <= '50') {
         var sum = 125 * x;
         hasil.value = 'Rp.' + parseFloat(sum * 1000);
     } else if (x >= '51' && x <= '100') {
         var sum = 120 * x;
         hasil.value = 'Rp.' + parseFloat(sum * 1000);
     } else if (x >= '101' && x <= '200') {
         var sum = 115 * x;
         hasil.value = 'Rp.' + parseFloat(sum * 1000);
     } else {
         hasil.value = 'error!';
     }
 }

And I still have some functions similar to that, it almost the same code I'm trying to make it simple, is it possible to make it in 1 function only?

Answer 1

Try:

  function maxval(x,maxval) {
    if(x >= '1' && x <= '50'){
      var sum = (maxval+10)* x;
      hasil.value = 'Rp.'+parseFloat(sum*1000);
    }
     else if (x >= '51' && x <= '100'){
       var sum = (maxval+5)* x;
       hasil.value = 'Rp.'+parseFloat(sum*1000);
     }
     else if(x >= '101' && x <= '200'){
       var sum = (maxval)* x;
       hasil.value = 'Rp.'+parseFloat(sum*1000);
     }
     else{
       hasil.value = 'error!';
     }
  }

By the way i assumed that maxval increments by 5, Cant get you a better solution without getting more details about functionality.

Answer 2

This would be my implementation. I don't agree with how you're handling your integers, but it's your coding style. I pass in an object of choice that has all of the values that I want. You don't need the logic, just the values. I hope nobody gets mad that I monkeypatch String . I'm assuming that your variable x is a string.

String.prototype.isBetween = function(lower, upper){
  int = parseInt(this)
  return int >= parseInt(lower) && int <= parseInt(upper)
}

max110 = {0: 120, 1: 115, 2: 110}
max115 = {0: 125, 1: 120, 2: 115}
function max(x, values) {
  let sum
  hasil.value = ''
  if (x.isBetween('1', '50')) {
    sum = values['0'] * x
  } else if (x.isBetween('51', '100')) {
    sum = values['1'] * x
  } else if (x.isBetween('101', '200')) {
    sum = values['2'] * x
  } else {
    hasil.value = 'error'
  }
  hasil.value = hasil.value ? 'error' : 'Rp.'+parseFloat(sum*1000);
}

Answer 3

function max(x, extra) {
  var sum_number = extra;
  if(x >= '1' && x <= '50'){
   sum_number += 120;
  }
  else if (x >= '51' && x <= '100'){
   sum_number += 115;
  }
  else if(x >= '101' && x <= '200'){
   sum_number += 110;
  }

  if(x < 1 && x > 200){
    hasil.value = 'error!';
  } else {
    hasil.value = 'Rp.'+parseFloat((sum_number) * x *1000);
  }
}

parameter extra can be 0 or 5 for function max110 or max115

Answer 4

Basically, you have two function which works the same way and returns the same with different values.

• The different values yould be stored in an array and you could use a single function for getting the index and then take the needed value out of the array with that index.

• So you need a better organisation of types of the variables, which if uses as number, it should be number and also for comparison, then it should be a number on both sides of the condition.

• Use a pure function , which does not alter a state of something, which is not given into the function.

• Use a check in the function for unwanted values and exit early with a first check at the lower border, in your case, it is zero and below, return -1 , because that is not an index of an array (and it is usually used to denote, that no index is found, like with Array#indexOf ).

• Then take the upper border for a check end exit early with a index value, no need for continuing else if structures.

• At the end return as well -1 for not found index.

Together:

 function getValue(x, maxArray) { var index = getIndex(x); if (index in maxArray) { return 'Rp.' + maxArray[index] * x * 1000; } return 'error!'; } function getIndex(x) { if (!x || x < 0) { return -1; } if (x <= 50) { return 0; } if (x <= 100) { return 1; } if (x <= 200) { return 2; } return -1; } var max110 = [120, 115, 110], max115 = [125, 120, 115]; console.log(getValue(-1, max110)); console.log(getValue(10, max110)); console.log(getValue(10, max115));