When Nested in a forEach Loop Goes Unnoticed

Question

When Nested in a forEach Loop Goes Unnoticed

I've encountered a problem with the code snippet below:

function isUniform (arr) {
    arr.forEach (function (el){
        console.log (el);
        if (arr [0] !== el) {
            return (false);
        }
    })
    return (true);
}

console.log (isUniform ([1, 1, 1, 1]));
console.log (isUniform ([2, 1, 1, 1]));
console.log (isUniform (["a", "b", "p"]));
console.log (isUniform (["b", "b", "b"]));

The intended functionality was for it to return "true" when all elements in an array are identical, and "false" otherwise. However, I'm facing an issue where it consistently returns "true". Upon further investigation, I discovered that JavaScript seems to be skipping over the single "if" statement.

UPDATE: This post is not a duplicate as I am seeking advice regarding my own code. Specifically, I wish to understand why the "if" statement nested within the forEach loop is being overlooked, which has not been addressed in similar queries.

javascript arrays

Answer 1

Answer №1

[5,5,5,5].every( (value, index, array) => value === array[0] )  //True
[7,7,8,7].every( (value, index, array) => value === array[0] )  //False

as discussed in this thread

Answer 2

[5,5,5,5].every( (value, index, array) => value === array[0] )  //True
[7,7,8,7].every( (value, index, array) => value === array[0] )  //False

as discussed in this thread

Answer 3

Answer №2

.forEach is not the best choice for this job as it disregards the callback result. It essentially duplicates the functionality of .every(), which has the added benefit of stopping the iteration once it determines it cannot return true.

function checkUniformity (arr) {
    return arr.every(function (element){
        return arr[0] === element
    });
}

console.log (checkUniformity ([1, 1, 1, 1]));
console.log (checkUniformity ([2, 1, 1, 1]));
console.log (checkUniformity (["a", "b", "p"]));
console.log (checkUniformity (["b", "b", "b"]));

If you were to write your own implementation, I recommend using a for-of loop so that you can break out of it.

function checkUniformity (arr) {
    for (const element of arr) {
        if (element !== arr[0]) {
            return false;
        }
    }
    return true;
}

console.log (checkUniformity ([1, 1, 1, 1]));
console.log (checkUniformity ([2, 1, 1, 1]));
console.log (checkUniformity (["a", "b", "p"]));
console.log (checkUniformity (["b", "b", "b"]));

Answer 4

.forEach is not the best choice for this job as it disregards the callback result. It essentially duplicates the functionality of .every(), which has the added benefit of stopping the iteration once it determines it cannot return true.

function checkUniformity (arr) {
    return arr.every(function (element){
        return arr[0] === element
    });
}

console.log (checkUniformity ([1, 1, 1, 1]));
console.log (checkUniformity ([2, 1, 1, 1]));
console.log (checkUniformity (["a", "b", "p"]));
console.log (checkUniformity (["b", "b", "b"]));

If you were to write your own implementation, I recommend using a for-of loop so that you can break out of it.

function checkUniformity (arr) {
    for (const element of arr) {
        if (element !== arr[0]) {
            return false;
        }
    }
    return true;
}

console.log (checkUniformity ([1, 1, 1, 1]));
console.log (checkUniformity ([2, 1, 1, 1]));
console.log (checkUniformity (["a", "b", "p"]));
console.log (checkUniformity (["b", "b", "b"]));

Answer 5

Answer №3

const checkUniformity = (array) => {
  let isUniform = true;
  
  array.forEach(element => {
    if(array[0] !== element) {
      isUniform = false;
    }
  });
  
  return isUniform;
};

console.log(checkUniformity([1, 1, 1, 1]));
console.log(checkUniformity([2, 1, 1, 1]));
console.log(checkUniformity(["a", "b", "p"]));
console.log(checkUniformity(["b", "b", "b"]));

Answer 6

const checkUniformity = (array) => {
  let isUniform = true;
  
  array.forEach(element => {
    if(array[0] !== element) {
      isUniform = false;
    }
  });
  
  return isUniform;
};

console.log(checkUniformity([1, 1, 1, 1]));
console.log(checkUniformity([2, 1, 1, 1]));
console.log(checkUniformity(["a", "b", "p"]));
console.log(checkUniformity(["b", "b", "b"]));

Answer 7

Answer №4

The use of return false; within the forEach function specifically serves to break the callback that was passed.

To maintain the boolean value, it is advised to add a variable for storage.

function checkUniformity (array) {
    var isUniform = true;
    array.forEach(function(element) {
        console.log(element);
        if(array[0] !== element) {
            isUniform = false;
        }
    });
    
    return isUniform;
}

Answer 8

The use of return false; within the forEach function specifically serves to break the callback that was passed.

To maintain the boolean value, it is advised to add a variable for storage.

function checkUniformity (array) {
    var isUniform = true;
    array.forEach(function(element) {
        console.log(element);
        if(array[0] !== element) {
            isUniform = false;
        }
    });
    
    return isUniform;
}

When Nested in a forEach Loop Goes Unnoticed

Answer №1

Answer №2

Answer №3

Answer №4

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