implement sum

sum() {

}

console.log(sum(2,1,3));

Legacy

function sum() {
    const args = arguments;
    let res = 0;
    for (let i=0; i<args.length; i++) {
        res += args[i];
    }
    return res;
}

console.log(sum(2,1,3));

Functions Rest Parameters

function sum(...args) {
    return args.reduce((pre, cur) => pre + cur, 0);
}
console.log(sum(2,1,3));

Contains case insensitive

const a = "This is a test";
const b = "IS";
a.toLowerCase().includes(b.toLowerCase())
!!a.match(new RegExp(b, "i"));
new RegExp(b, "i").test(a)

implement delay(ms)

const delay = (ms) => new Promise(res => setTimeout(res, ms))


function delay(milisec) {
    return new Promise(resolve => {
        setTimeout(() => { resolve('') }, milisec);
    })
}