If it is the basic JavaScript split function, look at documentation, JavaScript split() Method.

Basically, you just do this:

var array = myString.split(' -- ')

Then your two values are stored in the array - you can get the values like this:

var firstValue = array[0];
var secondValue = array[1];

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!

I think you want to use substring() (read more here: https://www.w3schools.com/jsref/jsref_substring.asp)

For example,

var str = "Hello world!";
var res = str.substring(1, 4);

would be equivalent to this Python code:

str = "Hello world!"
res = str[1:4]

res would be 'ell'. The start and end indices work the same as in Python (includes the start index, goes through but not including the end index.