Find an index of array item from another json array item

Question

I am looking to find out an index and group the item belong to in a parent json group, how can I do it? I am open to reformat the json as well if need be,

I tried JSON.stringify() but it returns the wrong index as well.

let Content = {
    group1: [
      [{content:"hello"},{content:"world"}],
      [{content:"hello1"},{content:"world"}],
      [{content:"hello2"},{content:"world"}],
      [{content:"hello3"},{content:"world"}],
      [{content:"hello4"},{content:"world"}],
      [{content:"hello5"},{content:"world"}],
    ],
    group2: [
      [{content:"hello10"},{content:"world"}],
      [{content:"hello11"},{content:"world"}],
      [{content:"hello12"},{content:"world"}],
      [{content:"hello13"},{content:"world"}],
      [{content:"hello14"},{content:"world"}],
      [{content:"hello15"},{content:"world"}],
    ],
  };
//   let currentItem = {type:'group2',index:5};
//   let currentItemContent = Content[currentItem.type][currentItem.index];
let obj = [{content:"hello15"},{content:"world"}];
let newIndex =  Content["group1"].indexOf(obj); 
let type = "group1"; 
if(newIndex < 0)
{
  type="group2"
  console.log(Content["group2"]);
  newIndex = Content["group2"].indexOf(obj); 
}
console.log({"type":type,"index":newIndex});

expected: {type:'group2',index:5}

adiga · Accepted Answer · 2019-07-03 18:33:52Z

1

Loop through the Content object using for...in. Check if the given array is in each group by using findIndex. Since both the objects in the array seem to be in order, you can simply compare the string returned by JSON.stringify

let Content={group1:[[{content:"hello"},{content:"world"}],[{content:"hello1"},{content:"world"}],[{content:"hello2"},{content:"world"}],[{content:"hello3"},{content:"world"}],[{content:"hello4"},{content:"world"}],[{content:"hello5"},{content:"world"}]],group2:[[{content:"hello10"},{content:"world"}],[{content:"hello11"},{content:"world"}],[{content:"hello12"},{content:"world"}],[{content:"hello13"},{content:"world"}],[{content:"hello14"},{content:"world"}],[{content:"hello15"},{content:"world"}]]}

function find(input, search) {
  for (const type in input) {
    const group = input[type];
    const index = group.findIndex(a => JSON.stringify(a) === JSON.stringify(search));
    
    if (index != -1)
      return { type, index }
  }
  return null
}

console.log(find(Content, [{content:"hello15"},{content:"world"}]))
console.log(find(Content, [{content:"hello"},{content:"world"}]))

edited Jul 3, 2019 at 18:33

answered Jul 3, 2019 at 18:28

adiga

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1 Comment

Vipul Over a year ago

Thank you so much Adiga for prompt answer, JSON.stringify comparison on both was something I kept missing. I have long (one liner) content instead of just "hello" and "world" and its working for that case as well. I just wanted to point that out in case anyone wondering whether it works for long sentences.

Akrion · Accepted Answer · 2019-07-03 19:07:33Z

You could also use Array.find in combination with Object.keys and Array.some. The array comparison you can do via JSON.stringify however remember that if your keys are in different order that would not work:

[{content:"world"},{content:"hello"}] vs [{content:"hello"},{content:"world"}]

would not match as you would expect since you are matching on strings and they are now different.

let Content = { group1: [ [{content:"hello"},{content:"world"}], [{content:"hello1"},{content:"world"}], [{content:"hello2"},{content:"world"}], [{content:"hello3"},{content:"world"}], [{content:"hello4"},{content:"world"}], [{content:"hello5"},{content:"world"}], ], group2: [ [{content:"hello10"},{content:"world"}], [{content:"hello11"},{content:"world"}], [{content:"hello12"},{content:"world"}], [{content:"hello13"},{content:"world"}], [{content:"hello14"},{content:"world"}], [{content:"hello15"},{content:"world"}], ], };
	    	
let findArray = (data, obj) => {
  let index, group = Object.keys(data).find((k,i) => {
    index = i
    return data[k].some(x => JSON.stringify(x) === JSON.stringify(obj))
  })
  return { index, group }
}

console.log(findArray(Content, [{content:"hello"},{content:"world"}]))
console.log(findArray(Content, [{content:"hello10"},{content:"world"}]))

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