function dropElements(arr, func) {
let output = arr.reduce((acc=[], elem) => {
if (func(elem)){
acc.push(arr.slice(arr.indexOf(elem)))
return acc
}
}, [])
return output
}
let tester = dropElements([1, 2, 3, 4,5,6,3,2,1], function(n) {return n >= 3;})
console.log(tester)
I want it to output [3,4,5,6,3,2,1]. But is printing copies of size decreasing arrays.
The statement of the problem: "Given the array arr, iterate through and remove each element starting from the first element (the 0 index) until the function func returns true when the iterated element is passed through it."
You can use Array#slice along with Array#findIndex to find the first index at which the callback function returns true.
function dropElements(arr, func) {
const idx = arr.findIndex(func);
return idx >= 0 ? arr.slice(idx) : [];
}
console.log(dropElements([1, 2, 3, 4, 5, 6, 3, 2, 1], n => n >= 3));If you specifically want to use Array#reduce, you could use a variable to store whether or not the callback has returned true for any element so far.
function dropElements(arr, func) {
let found = false;
return arr.reduce((acc, elem) => {
found = found || func(elem);
if (found) acc.push(elem);
return acc;
}, []);
}
console.log(dropElements([1, 2, 3, 4, 5, 6, 3, 2, 1], n => n >= 3));Use the shift method to remove the first element from the array until the array is empty or func(arr[0]) returns a truthy value. This method is inefficient as it could be, but it matches the problem statement. Particularly:
function dropElements(arr, func) {
while (arr.length > 0 && !func(arr[0])) {
arr.shift();
}
return arr;
}
let tester = dropElements([1, 2, 3, 4,5,6,3,2,1], function(n) {return n >= 3;});
console.log(tester);