Prepend a line number to each line of a text document

JavaScript version
const prependNumbers = (str) =>
str
.split(/\r?\n/)
.map((line, i) => `${(i + 1).toString().padStart(2, ' ')} ${line}`)
.join('\n');
TypeScript version
const prependNumbers = (str: string): string =>
str
.split(/\r?\n/)
.map((line, i) => `${(i + 1).toString().padStart(2, ' ')} ${line}`)
.join('\n');
Examples
prependNumbers(`one
two
three
four`);
/* Output */
/*
1 one
2 two
3 three
4 four
*/