How to refactor and make these if statements better?-CodePudding

I have a ton of if statements that I am tasked to refactor and make more readable.

The if statements rely on 2/3 JSON keys and I cannot think of a good way to make it better.

Does anyone have any tips for me?

These if statements were nested inside some other if statements, but I used a rules engine to help break it down. But I feel like a rules engine might not break this down to a better solution.

I’m thinking something like a map or lookup table, but I can’t process how to do this.

if (LM <= 15) {
  if (COMWT <= 25000) {
    COST = 225.0;
  }
  
  if (COMWT > 25000) {
    if (COMWT <= 30000) {
      COST = 275.0;
    }
  }
}

if (LM > 15) {
  if (LM <= 25) {
    if (COMWT <= 25000) {
      COST = 250;
    }
    
    if (COMWT > 25000) {
      if (COMWT <= 30000) {
        COST = 300.0;
      }
    }
  }
}

if (LM > 25) {
  if (LM <= 40) {
    if (COMWT <= 25000) {
      COST = 275;
    }
    
    if (COMWT > 25000) {
      if (COMWT <= 30000) {
        COST = 325.0;
      }
    }
  }
}

if (LM > 40) {
  if (LM <= 55) {
    if (COMWT <= 25000) {
      COST = 325;
    }
    
    if (COMWT > 25000) {
      if (COMWT <= 30000) {
        COST = 350.0;
      }
    }
  }
}

if (LM > 55) {
  if (LM <= 70) {
    if (COMWT <= 25000) {
      COST = 375;
    }
    
    if (COMWT > 25000) {
      if (COMWT <= 30000) {
        COST = 400.0;
      }
    }
  }
}

if (LM > 70) {
  if (LM <= 85) {
    if (COMWT <= 25000) {
      COST = 425;
    }
    
    if (COMWT > 25000) {
      if (COMWT <= 30000) {
        COST = 450.0;
      }
    }
  }
}

if (LM > 85) {
  if (LM <= 100) {
    if (COMWT <= 25000) {
      COST = 475;
    }
    
    if (COMWT > 25000) {
      if (COMWT <= 30000) {
        COST = 500.0;
      }
    }
  }
}

if (LM > 100) {
  if (LM <= 125) {
    if (COMWT <= 25000) {
      COST = 525;
    }
    
    if (COMWT > 25000) {
      if (COMWT <= 30000) {
        COST = 550.0;
      }
    }
  }
}

if (LM > 125) {
  if (LM <= 150) {
    if (COMWT <= 25000) {
      COST = 575;
    }
    
    if (COMWT > 25000) {
      if (COMWT <= 30000) {
        COST = 600.0;
      }
    }
  }
}

if (LM > 150) {
  if (LM <= 300) {
    if (COMWT <= 25000) {
      COST = LM * 3;
    }
    
    if (COMWT > 25000) {
      if (COMWT <= 30000) {
        COST = LM * 3.5;
      }
    }
  }
}

if (LM > 300) {
  if (COMWT <= 25000) {
    COST = LM * 2.5;
  }
  
  if (COMWT > 25000) {
    if (COMWT <= 30000) {
      COST = LM * 3;
    }
  }
}

CodePudding user response：

Store the checks in a variable and start with the greatest and work your way down to the lowest

const comwtLow = COMWT <= 25000;
const comwtHigh = COMWT > 25000 && COMWT <= 30000

let COST;

if (LM > 300 && comwtLow) COST = LM * 2.5;
else if (LM > 300 && comwtHigh) COST = LM * 3;
else if (LM > 150 && comwtLow) COST = LM * 3;
else if (LM > 150 && comwtHigh) COST = LM * 3.5;
else if (LM > 125 && comwtLow) COST = 575;
else if (LM > 125 && comwtHigh) COST = 600;
....

Without if/else you can do a data structure with an object and store the base part of the fees. Use a loop to find the fee structure that matches and generate the cost.

const fees = {
  300: {
    low: { multi: 2.5 },
    high: { multi: 3 },
  },
  150: {
    low: { multi: 3 },
    high: { multi: 3.5 },
  },
  125: {
    low: { flat: 575 },
    high: { flat: 600 },
  },
  0: {
    low: { flat: 225 },
    high: { flat: 275 },
  },
}

const feesValues = Object.keys(fees).map(Number).sort((a,b)=>b-a);

function getCost (lm, comwt) {
  const range = comwt <= 25000 ? "low" : "high";
  const feeData = fees[feesValues.find(value => value < lm)];
  const { multi = 0, flat = 0 } = feeData[range];
  return lm * multi   flat;
}

console.log(getCost(400, 10000));
console.log(getCost(130, 10000));

This code expects there to be matches on everything. If that is not the case, you need to add more logic and protection around it.

CodePudding user response：

You can do it by storing it into an array of objects.

Note: Please verify all conditions before using this code

const conditionList = [
    {
        high: 15,
        low: 0,
        comwt: [
            {
                high: 25000,
                low: 0,
                cost: lm => 225
            },
            {
                high: 30000,
                low: 25000,
                cost: lm => 275
            }
        ]
    },
    {
        high: 25,
        low: 15,
        comwt: [
            {
                high: 25000,
                low: 0,
                cost: lm => 250
            },
            {
                high: 30000,
                low: 25000,
                cost: lm => 300
            }
        ]
    },
    {
        high: 40,
        low: 25,
        comwt: [
            {
                high: 25000,
                low: 0,
                cost: lm => 275
            },
            {
                high: 30000,
                low: 25000,
                cost: lm => 325
            }
        ]
    },
    {
        high: 55,
        low: 40,
        comwt: [
            {
                high: 25000,
                low: 0,
                cost: lm => 325
            },
            {
                high: 30000,
                low: 25000,
                cost: lm => 350
            }
        ]
    },
    {
        high: 70,
        low: 55,
        comwt: [
            {
                high: 25000,
                low: 0,
                cost: lm => 375
            },
            {
                high: 30000,
                low: 25000,
                cost: lm => 400
            }
        ]
    },
    {
        high: 85,
        low: 70,
        comwt: [
            {
                high: 25000,
                low: 0,
                cost: lm => 425
            },
            {
                high: 30000,
                low: 25000,
                cost: lm => 450
            }
        ]
    },
    {
        high: 100,
        low: 85,
        comwt: [
            {
                high: 25000,
                low: 0,
                cost: lm => 475
            },
            {
                high: 30000,
                low: 25000,
                cost: lm => 500
            }
        ]
    },
    {
        high: 125,
        low: 100,
        comwt: [
            {
                high: 25000,
                low: 0,
                cost: lm => 525
            },
            {
                high: 30000,
                low: 25000,
                cost: lm => 550
            }
        ]
    },
    {
        high: 150,
        low: 125,
        comwt: [
            {
                high: 25000,
                low: 0,
                cost: lm => 575
            },
            {
                high: 30000,
                low: 25000,
                cost: lm => 600
            }
        ]
    },
    {
        high: 300,
        low: 150,
        comwt: [
            {
                high: 25000,
                low: 0,
                cost: lm => lm * 3
            },
            {
                high: 30000,
                low: 25000,
                cost: lm => lm * 3.5
            }
        ]
    }
];


function cal(lm, cmwt) {
    let costd = 0;
    conditionList.forEach(item => {
        if (lm >= item.low && lm <= item.high) {
            item.comwt.forEach(c => {
                if (cmwt >= c.low && cmwt <= c.high) {
                    costd = c.cost(lm);
                }
            });
        }
    });

    return costd;
}

console.log(cal(75, 24000));