String Challenge

StringChallenge.js

// - String Challenge -
// Have the function StringChallenge(str) read the str parameter being passed which 
// will contain the written out version of the numbers 0 - 9
// and the words "minus" or "plus" and convert the expression into an actual final number written out as well.
// For example: if str is "foursixminustwotwoplusonezero" then this converts to "46 - 22 + 10" 
// which evaluates to 34 and your program should return the final string threefour.
// If your final answer is negative it should include the word "negative."
// Examples:
// Input: "onezeropluseight"
// Output: oneeight
// Input: "oneminusoneone"
// Output: negativeonezero

function StringExpression(str) {
    let newString = str.slice(0);
    let dictionary = [
        ["zero", "0"],
        ["one", "1"],
        ["two", "2"],
        ["three", "3"],
        ["four", "4"],
        ["five", "5"],
        ["six", "6"],
        ["seven", "7"],
        ["eight", "8"],
        ["nine", "9"],
        ["minus", "-"],
        ["plus", "+"],
    ];
    dictionary.forEach((val) => {
        let regEx = new RegExp(val[0], "g");
        newString = newString.replace(regEx, val[1]);
    });
    let resString = eval(newString).toString();
    dictionary.slice(0, 10).forEach((val) => {
        let regEx = new RegExp(val[1], "g");
        resString = resString.replace(regEx, val[0]);
    });

    return resString.replace("-", "negative");
}
// keep this function call here
StringExpression(readline());