How to fix missing definitions of some standard js methods in typescript?

Question

JavaScript

I am writing a custom pipe. At the input and output - a string (9-digit number is expected).
It is necessary to bring 123456789 to the form (12) 345-67-89.
I tried:

value.splice ( 0, 0, "(" );
value.splice ( 2, 0, ") " );

But the tslint console throws an error. No method defined for string. Moreover, in the browser this method (on pure js) works properly.
Maybe I'm approaching the solution incorrectly or do I need to write the function prototype in *.d.ts?
In general, I don't know how to make this pipe work..

Answer 1

in the browser this method (on pure js) works properly

Somehow I don't believe it.
Yes, cut the string with the usual slice:

`(${value.slice(0, 2)}) ${value.slice(2, 5)}-${value.slice(5, 7)}-${value.slice(7)}`

Answer 2

"compilerOptions": {
    "lib": ["es6", "dom"],
}

Answer 3

There is no such method for strings. There is such a method for arrays. String !== Array. Break the string into an array of characters, twist them as you like, then put them back together.

let value = "123456789";
let numbers = value.split("");
numbers.splice ( 0, 0, "(" );
numbers.splice ( 3, 0, ")" );
numbers.join(""); // (12)3456789