How to refactor and make these if statements better?

Question

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;
    }
  }
}

Answer 1

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)=>ba); 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.

Answer 2

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));