How Does the Math. Max. Apply() Work?
Js Bin Var List = ["12","23","100","34","56", "9","233"]; Console. Log(Math. Max. Apply(Math, List)); the Above Code Finds the Max Number in the List. Can...
How does the Math.max.apply() work?.
<!DOCTYPE html>
<html>
<head>
<meta charset=utf-8 />
<title>JS Bin</title>
</head>
<body>
<script>
var list = ["12","23","100","34","56",
"9","233"];
console.log(Math.max.apply(Math,list));
</script>
</body>
</html>
The above code finds the Max number in the List. Can anyone tell me how does the below code work?. It seems it works if i pass null or Math.
console.log(Math.max.apply(Math,list));
Does all the user-defined/Native functions have call and apply method which we can use?.
5 Answers
apply accepts an array and it applies the array as parameters to the actual function. So,
Math.max.apply(Math, list);
can be understood as,
Math.max("12", "23", "100", "34", "56", "9", "233");
So, apply is a convenient way to pass an array of data as parameters to a function. Remember
console.log(Math.max(list)); # NaN
will not work, because max doesn't accept an array as input.
There is another advantage, of using apply, you can choose your own context. The first parameter, you pass to apply of any function, will be the this inside that function. But, max doesn't depend on the current context. So, anything would work in-place of Math.
console.log(Math.max.apply(undefined, list)); # 233
console.log(Math.max.apply(null, list)); # 233
console.log(Math.max.apply(Math, list)); # 233
Since apply is actually defined in Function.prototype, any valid JavaScript function object, will have apply function, by default.
On JavaScript ES6 just use the Spread operator:
var list = ["12","23","100","34","56","9","233"];
console.log(Math.max(...list));
// ^^^ Spread operator
Can anyone tell me how does the below code work?
Math.max.apply(Math,list)
Invokes a Math.max function with Math object to be used as a this reference in the function implementation (body) and list to be passed as an arguments.
So this eventually equals to
Math.max("12","23","100","34","56", "9","233")
It seems it works if i pass null or Math.
Obviously Math.max implementation doesn't use instance variable - there is no reason to do so. The native implementation would just iterate over arguments and find the maximum one.
Does all the user-defined/Native functions have call and apply method which we can use?.
Yes, every single function can be invoked using call or apply
References:
- MDN
.apply()documentation (credits to @RGraham)
I will start by saying Math.max(...numbers) and Function.prototype.apply() should only be used for arrays with relatively few elements. (...) and apply will either fail or return the wrong result if the array is too large
Math.max.apply(null | undefined | Math, numbers) is the same as Math.max(...numbers) so I would recommend Math.max(...numbers) for aesthetic reasons.
const numbers = [5, 6, 2, 3, 7];
const max = Math.max(...numbers);
console.log('max:', max);
// expected output: 7
const min = Math.min(...numbers);
console.log('min:', min);
// expected output: 2If you need to find the maximum element in a numeric array that is very large: use the Array.reduce() method.
Array.reduce() can be used to find the maximum element in a numeric array, by comparing each value:
const numbers = [5, 6, 2, 3, 7];
const getMax = (numbers) => numbers.reduce((a, b) => Math.max(a, b));
const getMin = (numbers) => numbers.reduce((a, b) => Math.min(a, b));
const max = getMax(numbers)
const min = getMin(numbers)
console.log('max:', max)
console.log('min:', min)Conclusion:
Numeric array that is relatively small: use Math.max(...numbers)
Numeric array that is very large: use the Array.reduce() method
Must Read
Math.max(val1, val2,...)
Math.max(1, 2, 3); // Math.max([value1[, value2[, ...]]])
value1, value2... are parameters and must be Numbers MDN Math.max
You can't pass array as Math.max parameters. To pass an array you have to use apply.
Alexander Ross has covered the video game industry for a decade, writing deep dives on game design, esports tournaments, VR developments, and gaming culture.
