在JS数组中找到最大的数字并返回变量名称

Question

I am trying to do something very simple but I can't get it to work. I have 3 variables:

abc = 123
def = 456
ghi = 789

I created array like this:

numbers = [abc, def, ghi]

Then I did this:

Math.max.apply(null, numbers)

It returned 789, then I tried to do:

numbers.indexOf(789)

but it returns 2 = index of ghi, problem is I wanna find "ghi" name exactly and I am struggling.

Answer 1

You need to store the labels in your array as well. JavaScript is not able to read your variable name during your program's execution:

 const abc = 123; const def = 456; const ghi = 789; const numbers = [ {label: 'abc', value: abc}, {label: 'def', value: def}, {label: 'ghi', value: ghi} ]; const max = Math.max.apply(null, numbers.map(v => v.value)); console.log(max); const maxObject = numbers.find(n => n.value === max); console.log(maxObject.label); 

Answer 2

If you use associative array then you dont need objects. here a sample solution using an array

 findMax = () => { // define the array let array = []; // filling items to the array array['a'] = 123; array['b'] = 456; array['c'] = 789; // variables for max and maxKey let max = 0; let maxKey = ''; // iterate through the assoc array for (var key in array) { if(max <= array[key]){ max = array[key]; maxKey = key } } console.log('max key ' + maxKey + ' max value ' + max); } 

 <input type='button' onclick='findMax()' value='find max' /> 

Answer 3

You should use Object instead of Array.

const abc = 123;
const def = 456;
const ghi = 789;

const numbers = { abc, def, ghi };
const max = Math.max.apply(null, Object.values(numbers));
const [variableName] = Object.entries(numbers).find(([el, val]) => val === max);

console.log(variableName)

Solution 👇

Answer 4

As you have unique labels for values, I would define your data as an object. Then you can build a simple reducer to return the label and the value together:

 const numbers = { abc: 123, def: 456, ghi: 789 } const [label, value] = Object.entries(numbers).reduce((a, b) => a[1] > b[1] ? a : b) console.log(label, value) 

The benefits of storing your variables in this way, is that you can quickly access your values by label simply by using numbers['abc'] for example.