This question already has answers here:
How to use a variable for a key in a JavaScript object literal?
(16 answers)
Closed 5 years ago.
console.log(a) ; // console window result= 1
console.log(b);// console window result= 2
var c = {a : b};// any recommendations here?
var d = JSON.stringify(c);
d = encodeURIComponent(d);
I need final result of d = {1:2};
You can use computed property
var c = {[a] : b};
Related
This question already has answers here:
Javascript How to define multiple variables on a single line?
(10 answers)
What is the purpose of the var keyword and when should I use it (or omit it)?
(19 answers)
Closed 2 months ago.
Can any one explain why this happens?
// Example 1
(function () {
var a = b = 5;
})();
console.log(b); // Output 5
var a = b = 5 and var b = 5 is totally different?
This question already has answers here:
What does the following code mean in javascript? [duplicate]
(2 answers)
Closed 6 years ago.
javaScript(variable)
var s = s || {};
s.c = {};
what purposes it will be use?
var s = s || {};
This means that if s is null, undefined or false (it computes to false), then an empty object {} will be assigned to s, so that the second line would not cause an error.
But this notation is inacurate. It should be something like:
var s = (typeof s == 'object') ? s : {};
because in the first example if s is a number the second line will still cause an error.
In the second example notation A ? B : C; is equal to:
if(A){
B;
}else{
C;
}
This question already has answers here:
Accessing nested JavaScript objects and arrays by string path
(44 answers)
Closed 7 years ago.
Silly example:
<script>
var a = {
'b' : {
'c' : "success!!"
}
};
var d = 'b.c';
</script>
How could I access success!! if I can't go for the obvious solution a.b.c or a['b']['c'], but instead have to use d? I tried a[d], which doesn't seem to do the trick. I also tried to fiddle with eval(). Is this even possible?
If it's really necessary to have the keys in a string separated with a dot, I would use split and reduce:
var success = d.split(".").reduce(function (obj, key) {
return obj[key];
}, a);
Try splitting
var a = {
'b' : {
'c' : "success!!"
}
};
var d = 'b.c';
var splat = d.split('.');
console.log(a[splat[0]][splat[1]]);
This question already has answers here:
How to find JavaScript variable by its name
(7 answers)
Closed 8 years ago.
I'm trying to find a way of using a string to refer to a variable.
Here is an example using jQuery:
var array = [1,2,3];
$('.array').click(function(){
var foo = $(this).attr('class');
return foo[1];
});
I want this to return the number '2' -
but as foo is a string it will return the sub string 'r'.
edit - the answer I was looking for was:
var array = [1,2,3];
$('.array').click(function(){
var foo = $(this).attr('class');
return eval(foo)[1];
});
I don't know if this is quite what you mean, but a Javascript object can do this.:
foo = {}; // create object
foo["string"] = [1,2,3]; // now the list [1,2,3] can be referenced
// by foo.string, or foo["string"]
console.log(foo["string"][1]); // Output with string.
Is that what you mean?
This question already has answers here:
dynamic keys for object literals in Javascript [duplicate]
(8 answers)
in javascript is it possible to construct an object literal with expressions evaluating to strings for property names? [duplicate]
(2 answers)
variable in javascript statement
(2 answers)
Closed 8 years ago.
I'm bored and messing with my console and I came up with the following code:
I was trying something like:
x = 16;
y = 26;
f = { x+y:"String!"};
expecting something or somehow to do:
Object {1626: "String!"}
Or at least
Object {42: "String!"}
I ended up with
x = 16;
y = 26;
eval("f = { "+x+y+":\"String!\"}");
Which returned as expected:
Object {1626: "String!"}
I've always been told to avoid eval() and never even think about using it due to something about security. Is there a way to use variables in declaring the property (Sorry if I don't know what it's called exactly)
x = 16;
y = 26;
f = {};
f[x+''+y] = "String!"; // For f[1626]
or
f[x+y] = "String!" // For f[42]
I made this exact same mistake when I started learning JavaScript: JavaScript set object key by variable
You first must make the object:
var f = {};
Then you can use variables to dynamically create keys:
var x = 16, y = 26;
f[x+y] = "Integer";
f[x.toString() + y.toString()] = "String";