数组的平均计算器（null arguments 返回 NaN）

Question

Uses rest parameter and for...of loop for an array...

 function average(...nums) { let total = 0; for(const num of nums) { total += num; } let avr = total / arguments.length; return avr; } console.log(average(2, 6)); console.log(average(2, 3, 3, 5, 7, 10)); console.log(average(7, 1432, 12, 13, 100)); // returns NaN - required to return 0. console.log(average());

Problem: for no arguments - console.log(average()); - Returns NaN where the correct answer must be 0.

Any good shorthand solution here?

Answer 1

Modify the function as -

function average(...nums) {
    if(nums.length === 0){
        return 0;
    }
    let total = 0;
    for(const num of nums) {
        total += num;
    }
    let avr = total / arguments.length;
    return avr;
}

Answer 2

You could just check arguments.length at the start of the function. Something like:

function average(...nums) {
    //check if no args are passed & return 0
    if(arguments.length === 0) return 0;
    //else
    let total = 0;
    for(const num of nums) {
    total += num;
    }
    let avr = total / arguments.length;
    return avr;
}

Answer 3

It's not very elegant but...

 const average = (...arr) => arr.reduce( ( acc, current ) => acc + current, 0 ) / (arr.length || 1); console.log(average(2, 6)); console.log(average(2, 3, 3, 5, 7, 10)); console.log(average(7, 1432, 12, 13, 100)); console.log(average());