JS random number (random number decimal)

I read some other articles on the Internet before , No direct access found [n,m] Two interval random values that are both decimals , So I wrote a

explain ：

1. min and max You can enter integers or decimals .
2. decimal： When no input or input is zero , The maximum number of decimal places is min and max The fractional part The largest number . for example ：randomNum(0, 6.88, 0) The maximum value of the decimal part is 99, for example 2.99, If you enter , Will be based on min and max also decimal Three to determine the maximum number of digits .
3. If you want random integer values , min and max Input integer , decimal No input or zero is OK , for example ：randomNum(1, 9, 0) perhaps randomNum(1, 9)

function randomNum(min = 0, max = 0, decimal=0) {
    
    let min_z = Math.trunc(min); //  The integer part of the minimum 
    let max_z = Math.trunc(max); //  The integer part of the maximum 
    //  Determine whether there is a decimal part , If there is no such thing as 0
    let min_x = isNaN(getDecimalNum(min)) ? 0 : getDecimalNum(min);  //  The fractional part of the minimum 
    let max_x = isNaN(getDecimalNum(max)) ? 0 : getDecimalNum(max);  //  The fractional part of the maximum 
    
    //  Distinguish between cases with and without decimals 
    if (min_x > 0 || max_x > 0 || decimal > 0) {
    
        //  Integer partial random number 
        let z = parseInt(Math.random() * (max_z - min_z + 1) + min_z, 10);
        //  Fractional random number 
        let x = 0;
        //  The maximum number of decimal random numbers 
        let max_decimal = min_x.toString().length > max_x.toString().length ? min_x.toString().length : max_x.toString().length;
        max_decimal = decimal > max_decimal ? decimal : max_decimal;
        //  Determine the random integer part , Whether it is equal to the minimum or maximum value 
        if(z == min_z || z == max_z){
    
            if(z == min_z){
    
                //  The integer partial random number is equal to the minimum value , Then you should start with the decimal part of the minimum value , To the maximum number of decimal places can be random 
                x = parseInt(Math.random() * (Math.pow(10, max_decimal) - min_x) + min_x, 10);
            }else{
    
                //  The integer partial random number is equal to the maximum value , Then we should 0 Start , To the decimal part of the maximum 
                x = parseInt(Math.random() * (max_x + 1), 10);
            }
        }else{
    
            //  The integer part is in the range of maximum and minimum values , From 0 To the maximum number of decimal places can be random 
            x = parseInt(Math.random() * (Math.pow(10, max_decimal)), 10);
        }
        return Number(`${
      z}.${
      x}`);
    } else {
    
        return parseInt(Math.random() * (max_z - min_z + 1) + min_z, 10);
    }
}

//  Get the decimal part of the value 
function getDecimalNum(data){
    
    return Number(data.toString().split('.')[1]);
}


// Use 
console.log(` Random number is ：${
      randomNum(0, 6.8, 2)}`)