Question 286832 in Javascript Question posted in
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Javascript – Check if an array has an object with a certain property

I have an array of objects:

const arr = [
{ puzzle: [1,3,4,8,0,2,7,6,5], children: [] }, 
{ puzzle: [1,2,3,4,5,6,7,8] }
]

And I have an object:

const element = { puzzle: [1,3,4,8,0,2,7,6,5], children: ["1"]}

Im trying to see if element.puzzle is a value for a property of any of the objects in the array – in this particular example
element.puzzle === arr[0].puzzle, but a few methods I tried give the wrong result, so obviously I`m wrong…

array.some() method gives wrong result

arr.some(item => item.puzzle === element.puzzle) // gives false
arr.find(item=>item.puzzle === element.puzzle) //gives undefined
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2

Answers


  1. 0

    For each item in the array, check to see if at least one has a puzzle that has the same length and matches every index/value in the element’s puzzle.

    const
  arr = [
    { puzzle: [1,3,4,8,0,2,7,6,5], children: [] }, 
    { puzzle: [1,2,3,4,5,6,7,8] }
  ],
  element = { puzzle: [1,3,4,8,0,2,7,6,5], children: ["1"]}

const arrHasPuzzle = arr.some(({ puzzle }) =>
  puzzle.length === element.puzzle.length &&
  puzzle.every((e, i) => e === element.puzzle[i]));

console.log(arrHasPuzzle); // true
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  2. 0

    The problem is that the both of the puzzles are different instances of arrays. And since arrays are objects they’re treated as different values when comparing equality, even if they contain the same values.

    [1,2,3] === [1,2,3] //false

    Instead, you’re going to have to compare the values of every element in both arrays with each other to tell if they’re "equivalent".

    arr.some(item => item.puzzle.every((e, i) => element.puzzle[i] === e))
arr.find(item => item.puzzle.every((e, i) => element.puzzle[i] === e))
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