2804. Array Prototype ForEach π
Description
Write your version of method forEach
that enhances all arrays such that you can call the array.forEach(callback, context)
method on any array and it will execute callback
on each element of the array. Method forEach
should not return anything.
callback
accepts the following arguments:
currentValue
- represents the current element being processed in the array. It is the value of the element in the current iteration.index
- represents the index of the current element being processed in the array.array
- represents the array itself, allowing access to the entire array within the callback function.
The context
is the object that should be passed as the function context parameter to the callback
function, ensuring that the this
keyword within the callback
function refers to this context
object.
Try to implement it without using the built-in array methods.
Example 1:
Input: arr = [1,2,3], callback = (val, i, arr) => arr[i] = val * 2, context = {"context":true} Output: [2,4,6] Explanation: arr.forEach(callback, context) console.log(arr) // [2,4,6] The callback is executed on each element of the array.
Example 2:
Input: arr = [true, true, false, false], callback = (val, i, arr) => arr[i] = this, context = {"context": false} Output: [{"context":false},{"context":false},{"context":false},{"context":false}] Explanation: arr.forEach(callback, context) console.log(arr) // [{"context":false},{"context":false},{"context":false},{"context":false}] The callback is executed on each element of the array with the right context.
Example 3:
Input: arr = [true, true, false, false], callback = (val, i, arr) => arr[i] = !val, context = {"context": 5} Output: [false,false,true,true]
Constraints:
arr
is a valid JSON arraycontext
is a valid JSON objectfn
is a function0 <= arr.length <= 105
Solutions
Solution 1
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