JavaScript- Delete all Occurrences in a JS Array

function fun(a, e) {
    if (!a.includes(e)) {
        return -1;
    }

    return a.filter(
        (item) => item !== e);
}

const a = [1, 2, 3, 4, 2, 5, 2];
const res = fun(a, 2);

console.log(res);

function fun(a, e) {
    if (!a.includes(e)) {
        return -1;
    }

    for (let i = a.length - 1; i >= 0; i--) {
        if (a[i] === e) {
            a.splice(i, 1);
        }
    }
    return a;
}

const a = [1, 2, 3, 4, 2, 5, 2];
const res = fun(a, 2);

console.log(res);

function fun(a, e) {
    if (!a.includes(e)) {
        return -1;
    }

    let a1 = [];
    a.forEach(item => {
        if (item !== e) {
            a1.push(item);
        }
    });
    return a1;
}

const a = [1, 2, 3, 4, 2, 5, 2];
const res = fun(a, 2);
console.log(res);

function fun(a, e) {
    return a.reduce((acc, c) => {
        if (c !== e) {
            acc.push(c);
        }
        return acc;
    }, []);
}

let a = [1, 2, 3, 4, 2, 5, 2];
let e = 2;
let a1 = fun(a, e);
console.log(a1);