Accessing elements of both arrays and objects can be done by iterating through them using one code

Question

Accessing elements of both arrays and objects can be done by iterating through them using one code

Suppose I have a function that receives either an object or an array. The goal is to iterate through each element and perform some action on each element along the way. While looping through an array can be achieved using forEach() or a regular for loop, handling objects requires the usage of a for-in loop with an additional check using hasOwnProperty().

Is there a more universal approach that can handle both arrays and objects?

Here's my attempt at iterating through an object/array named 'value', but there seems to be no console messages displaying in case of objects:

keysArray = Object.keys(value);
for(let key in keysArray) {
    console.log(value[key])
}

javascript arrays iteration

Answer 1

Answer №1

You have the option to utilize a generator function called "entries" which iterates through an object or array:

function* entries(o) {
    if (Array.isArray(o))
        for (let i=0; i<o.length; i++)
            yield [i, o[i]];
    else
        for (const p in o)
            yield [p, o[i]];
}
// Another way is by using built-in iterators:
function entries(o) {
    return Array.isArray(o) ? o.entries() : Object.entries(o).values();
}

To use this function, you can call it as follows:

for (const [key, value] of entries(something)) {
    console.log(key, value);
}

Additionally, you can modify the function to only retrieve keys or values if needed.

Answer 2

You have the option to utilize a generator function called "entries" which iterates through an object or array:

function* entries(o) {
    if (Array.isArray(o))
        for (let i=0; i<o.length; i++)
            yield [i, o[i]];
    else
        for (const p in o)
            yield [p, o[i]];
}
// Another way is by using built-in iterators:
function entries(o) {
    return Array.isArray(o) ? o.entries() : Object.entries(o).values();
}

To use this function, you can call it as follows:

for (const [key, value] of entries(something)) {
    console.log(key, value);
}

Additionally, you can modify the function to only retrieve keys or values if needed.

Answer 3

Answer №2

// This function works with either objects or arrays

function performAction(data) {
  let myLoopable = data;

  // If the input is an object, convert it to an array
  if (!Array.isArray(data)) {
    myLoopable = Object
      .keys(data) // Retrieve keys as an array
      .reduce((accumulator, currentKey) => [...accumulator, data[currentKey]], []); // Get values as an array
  }

  myLoopable.forEach(element => console.log(element));
}

This code snippet serves as an illustration and not a foolproof solution. It's crucial to verify whether the input is an object or something else in order to ensure your function operates smoothly.

Answer 4

// This function works with either objects or arrays

function performAction(data) {
  let myLoopable = data;

  // If the input is an object, convert it to an array
  if (!Array.isArray(data)) {
    myLoopable = Object
      .keys(data) // Retrieve keys as an array
      .reduce((accumulator, currentKey) => [...accumulator, data[currentKey]], []); // Get values as an array
  }

  myLoopable.forEach(element => console.log(element));
}

This code snippet serves as an illustration and not a foolproof solution. It's crucial to verify whether the input is an object or something else in order to ensure your function operates smoothly.

Accessing elements of both arrays and objects can be done by iterating through them using one code

Answer №1

Answer №2

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