How do you modify an array in javascript?

Modify all Elements in an Array #

To change the value of all elements in an array:

1. Use the forEach[] method to iterate over the array. The method takes a function that gets invoked with the array element, its index and the array itself.
2. Use the index of the current iteration to change the corresponding array element.

index.js

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const arr = ['a', 'b', 'c'];

arr.forEach[[element, index] => {
  arr[index] = element + index;
}];

console.log[arr]; // 👉️ ['a0', 'b1', 'c2']

The function we passed to the Array.forEach[] method gets invoked with each element, its corresponding index and the entire array.

We used the index to change the value of the array element at the specific position.

We could have achieved the same result by using a plain for loop. However, for loops are a bit more verbose and indirect.

index.js

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const arr = ['a', 'b', 'c'];

for [let index = 0; index  {
    if [value === "A2" || value === "A5"] {
        values.splice[index - count++, 1];
    };
}];
console.log[values];

// Expected: [ 'A0', 'A1', 'A3', 'A4', 'A6', 'A7', 'A8' ]

To insert elements before:

if [value === "A0" || value === "A6" || value === "A8"] {
    values.splice[index - count--, 0, 'newVal'];
};

// Expected: ['newVal', A0, 'A1', 'A2', 'A3', 'A4', 'A5', 'newVal', 'A6', 'A7', 'newVal', 'A8' ]

To insert elements after:

if [value === "A0" || value === "A6" || value === "A8"] {
    values.splice[index - --count, 0, 'newVal'];
};

// Expected: ['A0', 'newVal', 'A1', 'A2', 'A3', 'A4', 'A5', 'A6', 'newVal', 'A7', 'A8', 'newVal']

To replace an element:

if [value === "A3" || value === "A4" || value === "A7"] {
    values.splice[index, 1, 'newVal'];
};

// Expected: [ 'A0', 'A1', 'A2', 'newVal', 'newVal', 'A5', 'A6', 'newVal', 'A8' ]

Note: if implementing both 'before' and 'after' inserts, code should handle 'before' inserts first, other way around would not be as expected

How do you modify an array?

Can an array be modified?

How do you change an element in an array?

How do you manipulate an array of objects in JavaScript?