Flattening each array in the array

JavaScript
1

So I need to flatten each array in the array in order

" given a nested array or arrays, return a new, flat array with all the elements of all the nested arrays in their original order"

so I was gonna use for each to push each flattened array to a new array


function flattenArray (arrayOfArrays) {
 var originalArray = arrayOfArrays
// using this to save the unmodified array cos flattened messes with it 
 var flattenedArray = []
//creating place to store result of flattening each array in array
 arrayOfArrays.forEach(flatten)
// creating flattened array by calling it on array of arrays
 arrayOfArrays = originalArray
//making sure original arrayofarrays is unmodified

 function flatten (arrayItem)
 {
    flattenedArray.push (arrayItem.flat())
 }
//function to flatten array
 return flattenedArray;

}

however it wont accept .flat() for some reason
here’s the result I get when trying to run itimage

2

Ok I dont think you can use flat() on an array so this should work instead

function flattenArray (arrayOfArrays) {
 var arr1 = []

  arrayOfArrays.forEach(flatten)
 return arr1

 function flatten (x)
 {
   for(i=0;i<x.length;i++)
   arr1.push(x[i])
 }
 console.log(arr1)
  // given a nested array or arrays, return a new, flat array with all the elements of all the nested arrays in their original order
}
3

2 things are wrong here

Like I said in the other answer, assignment does not create a new copy of an array. All it does is create a reference to the original array. You need to use an immutable method to create a new array

flattenedArray.push (arrayItem.flat())

There is no flat() method in javascript. And here you are trying to call the flat() method on the passed in item.

Add this line and you’ll see what I mean

 function flatten (arrayItem)
 {
    // add me
   const methods = Object.getOwnPropertyNames(arrayItem).filter(
                        p => typeof arrayItem[p] === "function");
  // add me too
   console.log({ arrayItem, methods, typeOf: typeof arrayItem });
    flattenedArray.push (arrayItem.flat())
 }
//function to flatten array
 return flattenedArray;

}
4

beat me to it. Is your code still failing?

5

nah it works now thanks though :smiley: Ill leave the thread though for other people who have a similar mixup

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