Number Shortener - Refactored

the_truncanator.js

/**
 * Refactored by Vampiire on 5/19/17.
 * Now will correctly truncate regardless of how many integer digits are in place 
 * (previously only worked for 1 integer digit)
 * 
 * Looks for the index value of the decimal and treats this as the start of the slice
 * Seeks beyond the decimal point (+1) to the number of decimals specified by the user 
 * Adds a 6 at this point so it will round up correctly to the number of decimals requested
 * 
 */

// pass in any number and specify the number of decimal places to truncate the value to:

function theTruncanator(num, decimals){

    num = num.toString();
    const start = num.indexOf('.'); // start at the decimal
    const end = start+1+decimals; // end 1 past the decimal place + number of decimals passed by user

    if(num[end] === "5"){
        num = num.slice(0,start) + num.slice(start, end) + 6;
        return Number(Number(num).toFixed(2));
    }

    return Number(Number(num).toFixed(decimals));
}