JavaScript functions have a built-in object called the arguments object.
The argument object contains an array of the arguments used when the function was called (invoked).
This way you can simply use a function to find (for instance) the highest value in a list of numbers:
Example
function findMax() {
let max = -Infinity;
for (let i = 0; i < arguments.length; i++) {
if (arguments[i] > max) {
max = arguments[i];
}
}
return max;
}
Or create a function to sum all input values:
Example
function sumAll() {
let sum = 0;
for (let i = 0; i < arguments.length; i++) {
sum += arguments[i];
}
return sum;
}
If a function is called with too many arguments (more than declared), these arguments can be reached using the arguments object.
Arguments are Passed by Value
The parameters, in a function call, are the function's arguments.
JavaScript arguments are passed by value: The function only gets to know the values, not the argument's locations.
If a function changes an argument's value, it does not change the parameter's original value.
Changes to arguments are not visible (reflected) outside the function.
Objects are Passed by Reference
In JavaScript, object references are values.
Because of this, objects will behave like they are passed by reference:
If a function changes an object property, it changes the original value.
Changes to object properties are visible (reflected) outside the function.
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