Use json to populate a case switch statement in React

Question

I have the following switch/case statement which returns data from the json object below. In reality this will be very long!

Switch statement

switch(val){
    case 'chicken':
        return json['meat']['main'][val]; 
        break;
    case 'beef':
        return json['meat']['main'][val]; 
        break
    case 'lamb':
        return json['meat']['main'][val]; 
        break;
    case 'pork':
        return json['meat']['main'][val]; 
        break;
    default:
        return '';
}

json object

json={
  "meat": {
    "main": {
      "chicken": "Roast chicken and vegetables",
      "beef": "Beef and Yorkshire pudding",
      "lamb": "Lamb shank with red currant gravy",
      "pork": "Pork and apple sauce",
    }
  }
}

As you can see, the switch statement is very repetitive as every case statement returns the same expression (although the value it returns will be different as it is accessing a variable key [val] in the object).

In reality my json file is huge, so I want to avoid manually typing out a case statement for each meat (chicken, beef, lamb, pork). Instead I would like to iterate through my json object getting the value at json['meat']['main'][i] (where i is a counter) to create each case. Is this possible? And if not, is there an alternative approach?

Many thanks!

Katie

can you explain a bit more of your use case? For the above case you might not need a switch statement. return json.meat.main[val] should work — SpiritOfDragon
– SpiritOfDragon, Commented Apr 9, 2020 at 15:47
Your switch statement doesn't make any sense. If you use json['meat']['main'][val], you are directly accessing correct value. — Sarthak Aggarwal
– Sarthak Aggarwal, Commented Apr 9, 2020 at 15:48

twharmon · Accepted Answer · 2020-04-09 15:52:14Z

2

Is this what you need?

let json = {
  "meat": {
    "main": {
      "chicken": "Roast chicken and vegetables",
      "beef": "Beef and Yorkshire pudding",
      "lamb": "Lamb shank with red currant gravy",
      "pork": "Pork and apple sauce",
    }
  }
}


const search = (obj, val) => {      
  const keys = Object.keys(obj)
  for (const key of keys) {
    if (typeof obj[key] === 'string') {
      if (key === val) {
        return obj[key]
      }
    } else {
      const description = search(obj[key], val)
      if (description) {
        return description
      }
    }
  }
  return ''
}


const description = search(json, 'beef')
console.log(description)

answered Apr 9, 2020 at 15:52

twharmon

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4 Comments

SpiritOfDragon Over a year ago

isn't it something like this? return json.meat.main['chicken']

twharmon Over a year ago

I'm assuming val could be something like "apple", which wont fall under the "meat" category. So you can't do json.meat.main['apple'] or json.fruit.main['apple'].

SpiritOfDragon Over a year ago

Yes. it makes sense if that is the case. but from the question he needs a simple return of meat.main['val']. Instead I would like to iterate through my json object getting the value at json['meat']['main'][i]

Katie7 Over a year ago

@twharmon - you have nailed it! That's so clever - loving your answer and it works perfectly when I put it into my real code, which is much more complex. Thank you so much! And you have interpreted my question exactly as I intended. You're right that I need everything to be variable, so would need to work for apple and other things etc. Thanks again - really happy with this solution :-)

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