I have done it for you. Hope you like this. Thanks!

The indexOf() method returns the first index at which a given element can be found in the array, or -1 if it is not present. Syntax: indexOf(searchElement) E.g

let text = "John.Smith";

console.log(text.indexOf('.')); // 4

let text = "John.Smith";
// let result = text.split('.')[0];
let result = text.slice(0, text.indexOf('.'));

document.getElementById("demo").innerHTML = result;

According to ECMAScript6 ES6, the clean way is destructuring arrays:

const input = 'john smith~123 Street~Apt 4~New York~NY~12345';

const [name, street, unit, city, state, zip] = input.split('~');

console.log(name); // john smith
console.log(street); // 123 Street
console.log(unit); // Apt 4
console.log(city); // New York
console.log(state); // NY
console.log(zip); // 12345

You may have extra items in the input string. In this case, you can use rest operator to get an array for the rest or just ignore them:

const input = 'john smith~123 Street~Apt 4~New York~NY~12345';

const [name, street, ...others] = input.split('~');

console.log(name); // john smith
console.log(street); // 123 Street
console.log(others); // ["Apt 4", "New York", "NY", "12345"]

I supposed a read-only reference for values and used the const declaration.

Enjoy ES6!