This question already has answers here:
What's the difference between ++i and i++ in JavaScript [duplicate]
(6 answers)
Closed 1 year ago.
I want to increase object value just like loop i++ , but in object didnt worked ,
how to increase this value ? any methods?
const object = {
price:30
}
console.log(object.price++);
using ++ like that is the post-increment operator meaning object.price++ returns object.price first then increments. You want the pre-increment operator ++object.price.
const object = {
price:30
}
console.log(++object.price);
Related
This question already has answers here:
javascript i++ vs ++i [duplicate]
(8 answers)
++someVariable vs. someVariable++ in JavaScript
(7 answers)
Closed 1 year ago.
when i use ++ operator in javascript, why I get the value at last is 100 not 101?
I want to know the detail of the ++ operator in javascript?
let value = 100;
value = value++;
console.log(value); // 100 why the value is 100 at last
Because when you have the assignment operator, the right-hand operand is evaluated first, then that value is assigned to the receiver on the left.¹
So here's what happens in value = value++:
Read the value of value (100) and set it aside (since we'll need it in a minute).
Increase the value of value by one (making it 101).
Take the value from #1 (100) as the result value of the right-hand operand.
Store that value in value.
¹ In specification terms it's slightly more complicated than that, but the details aren't important here.
That's because <value>++ returns the previous value and not the new one
If you want it to return the new value use ++<value>
This question already has answers here:
What is destructuring assignment and its uses?
(3 answers)
What does this symbol mean in JavaScript?
(1 answer)
Javascript object bracket notation ({ Navigation } =) on left side of assign
(5 answers)
Closed 2 years ago.
I've recently came across this particular code:
const arr = [1,2,3];
const { length } = arr;
for (i = 0; i<=length; i++){
console.log(i)
}
Apparently this (const { length } = arr;) somehow works, but I haven't found any information on the Internet on either how or why should this actually work.
My question: how does this { } construction work and why doesn't it work when I change { length } to anything else, like { arrlength }? Can we possibly use this construction with other array's properties and how?
This question already has answers here:
JavaScript closure inside loops – simple practical example
(44 answers)
Closed 5 years ago.
I have this array:
var arr = [];
var i =
1) There:
setInterval ( function push(arr) {arr.push(i+1)} , 5*1000)
you're shadowing the arr variable (that is declaring a new variable which hides the external one). You're thus pushing to undefined. There's of course the same problem when you read the values.
2) If you always push i+1 you always push 1. You probably want i++
Simply do
setInterval ( function push() {arr.push(i++)} , 5*1000)
This question already has answers here:
How to observe value changes in JS variables
(3 answers)
Closed 5 years ago.
function getPercCalculated(x){
return (x*9.3)/100;
}
var x = 10;
var perx = getPercCalculated(x);
Instead of this I would like to call the getPercCalculated using dot operator like
var perx = x.getPercCalculated()
Can someone help me..!!
Number.prototype.getPercCalculated= function(){
return (this*9.3)/100;
};
This will attach the getPercCalculated to every number in your code tough
This question already has answers here:
How do I check if an array includes a value in JavaScript?
(60 answers)
Closed 10 years ago.
var a=new Array;
for (j=0;j<=10;j++) {
a[j]=Math.floor(Math.random()*99)+2
}
var check=Math.floor(Math.random()*99)+2
So how do I check whether check is a value of any of the a[j] (that is a[0] to a[10])? A good and simple method?
Try this:
a.indexOf(check) > -1