how to write the end of any string in the slicing in javascriipt code example

Example 1: js string slicing

const str = 'The quick brown fox jumps over the lazy dog.';

console.log(str.slice(31));
// expected output: "the lazy dog."

console.log(str.slice(4, 19));
// expected output: "quick brown fox"

Example 2: string splice

newStr = str.split(''); // or newStr = [...str];
newStr.splice(2,5);
newStr = newStr.join('');