como usar o indentString no javascript es6

Indents each line in the provided string.

Use String.replace and a regular expression to add the character specified by indent count times at the start of each line. Omit the third parameter, indent, to use a default indentation character of ' '.

const indentString = (str, count, indent = ' ') => str.replace(/^/gm, indent.repeat(count));

indentString('Lorem\nIpsum', 2); // '  Lorem\n  Ipsum'
indentString('Lorem\nIpsum', 2, '_'); // '__Lorem\n__Ipsum'

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