const origin = pattern
    let negative = false

    // > An optional prefix "!" which negates the pattern;
    if (pattern.indexOf('!') === 0) {
        negative = true
        pattern = pattern.substr(1)
    }

    pattern = pattern
        // > Put a backslash ("\") in front of the first "!" for patterns that
        // >   begin with a literal "!", for example, `"\!important!.txt"`.