Loading Please Wait...
Function parameters are the names listed in the function definition.
Function arguments are the real values passed to (and received by) the function.
A JavaScript function does not perform any checking on parameter values (arguments).
function functionName(parameter1, parameter2) {
// code to be executed
}
JavaScript function definitions do not specify data types for parameters.
JavaScript functions do not perform type checking on the passed arguments.
JavaScript functions do not check the number of arguments received.
If a function is called with missing arguments (less than declared), the missing values are set to undefined.
Sometimes this is acceptable, but sometimes it is better to assign a default value to the parameter.
function myFunction(x, y) {
if (y === undefined) {
y = 2;
}
}
ES6 allows function parameters to have default values.
function myFunction(x, y = 10) {
return x + y;
}
myFunction(5);
The rest parameter (...) allows a function to treat an indefinite number of arguments as an array.
function sum(...args) {
let sum = 0;
for (let arg of args) sum += arg;
return sum;
}
let x = sum(4, 9, 16, 25, 29, 100, 66, 77);
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.
x = findMax(1, 123, 500, 115, 44, 88);
function findMax() {
let max = -Infinity;
for (let i = 0; i < arguments.length; i++) {
if (arguments[i] > max) {
max = arguments[i];
}
}
return max;
}
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.
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.
How you feel about this blog:
Share this blog on:
If you find any error in the turtorials, or want to share your suggestion/feedback, feel free to send us email at: info@lynxsia.com
Contact Us
We are concern with various development process like website design & development, E-commerce development, Software development, Application development, SMS & Bulk SMS Provider, PWA Development, and many more..
Copyright © , Lynxsia IT Solutions, All rights reserved