apply vs call

apply() and call() are common methods to invoke a function.

Following is the syntax of these methods, where fn represents a given function:

fn.apply(context, arrayOfArguments);
fn.call(context, arg1, arg2, ...);

As you see, apply requires the arguments as an array, whereas call requires the arguments to be listed explicitly.

For example, the following function returns the sum of three numbers.

const sum = (a, b, c) => a + b + c;

sum.apply(null, [1, 2, 3]); // 6
sum.call(null, 1, 2, 3); // 6

You can use this mnemonic to remember the differences between apply and call:

A is for array

C is for comma