This question already has answers here:
return a string inside a function
(2 answers)
Closed 1 year ago.
Here is the challenge I need help with:
Create a variable called myFriend using one of the variable declarations described above (var, let, or const). Set the variable you created to contain your friend's name. Inside the greetings function, return the string: "Greetings [your-friend's-name].
New to this, but I can't seem to find out where the error is. Probably easy for you guys but, I'll get there.enter image description here
var myFriend = "Sara"
function greetings() {
let greetings = "greetings, " + myFriend
}
console.log('results: ,'+greetings());
You forgot the return statement.
return greetings;
Related
This question already has answers here:
How can I pass variable into an evaluate function?
(7 answers)
How do i return a value from page.evaluate() in puppeteer?
(3 answers)
Closed 1 year ago.
I'm kind of new to JavaScript but I'm using a function that takes another arrow function as a parameter. All I need to do in the function is simply set a value to some variable I have declared before it. From my understanding, var means it has global scope, so I'm not really sure why I cant use the variable. If I try to pass it in the parameter I get undefined. I'll paste the 2 lines of code giving me issues
var thing = events[i]["Address"];
await page.evaluate( () => document.querySelector('[class="form-control tt-input"]').value = thing)
This question already has answers here:
Using a string to access a variable
(3 answers)
Closed 3 years ago.
I have a JS function as below
// A simple array where we keep track of things that are filed.
filed = [];
function fileIt(thing) {
// Dynamically call the file method of whatever 'thing' was passed in.
thing.file();
// Mark as filed
filed.push(thing);
}
Now, function fileIt(thing) is working well when called as below
fileIt(AuditForm);
Whereas, its giving error at line thing.file(); when i am trying to pass a variable like below
var formID = obj.id;
fileIt(formID);
Variable formID has same value and i.e. "AuditForm" what's wrong here. Kindly suggest.
If obj.id is the string AuditForm, then you have no choice but to use dynamic property notation on the global window object, or use eval if you didn't declare AuditForm with var on the global scope:
If you declare AuditForm with var on the global scope:
fileIt(window[formID]);
If you don't:
fileIt(eval(formID));
Do note that eval is a very poor option, as if obj.id can be interpreted as other code, e.g. another eval call which will be evaluated, then malicious operations can be performed. Example:
const obj = {
id: "eval('alert(\"Inside an eval script!\")')"
};
eval(obj.id);
This question already has answers here:
Calling function inside object using bracket notation
(2 answers)
Closed 6 years ago.
I rather have a seemingly trivial issue, but am not able to figure out an efficient approach.
I have a list of about 50 functions to be called such as :
globalClient.funcA(...)
globalClient.funcB(...)
globalClient.funcC(...)
My code should ideally dynamically create the name of the function (funcA / funcB/ funcC and then proceed to actually call that function. My approach below does not work (please note that these aren't exactly the actual names of the functions. I'm only giving these arbitrary names for simplicity of understanding):
var functionName = 'func'.concat('A');
globalClient.functionName
The second line is where it errors out. Now JS thinks that functionName itself is the name of the function. What I want it to do is resolve functionName to funcA and then call globalClient.funcA(...) instead.
I've thought about implementing a switch / case for this but I'm sure there is a far simpler appraoch. Any ideas?
You could use the bracket notation as property accessor.
globalClient[functionName]()
You can use the [ ] operator for accessing the properties.
var globalClient = {
funcA: function(){
console.log('funcA is called');
}
}
var functionName = 'func'.concat('A');
globalClient[functionName]();
This question already has answers here:
Convert string to variable name in JavaScript
(11 answers)
Closed 8 years ago.
I know this piece of code is wrong, but I wonder if there is any way this would be possible.
var createVariableFromParameter = function(myName) {
var myName = [];
return myName;
}
Thank you.
EDIT: I found the solution here: Convert string to variable name in Javascript
I think it's not possible, and even if it could be done, why would you want to do it? There is no meaning in creating variables with random names...
I don't know why you should need it??
But I think true way is :
function create(myvar) { myvar = [];}
var a;
create(a);
function create() { return [];}
var b = new create();
This question already has answers here:
Get variable name. javascript "reflection"
(4 answers)
JavaScript: Get Argument Value and NAME of Passed Variable [duplicate]
(7 answers)
Closed 8 years ago.
I was wondering if it's possible to get the name of a variables in javascript or JQuery.
Suppose that I declare a variable in javascript like:
var customerNr = "456910";
If a function receive a variable, how can i return the name of the variable?
For example:
function getNameOfVariable(someVariable){
//return name of someVariable;
}
If I call this function like this:
getNameOfVariable(customerNr);
The function has to return a string whose value is "customerNr".
How can I do this in jquery or javascript? Some kind of reflection?
That is simply not possible!
The passed parameter doesn't even have to have a name. It could be a return value of a function or a raw literal (like "string" or 3).
No, this is not possible. Only values are transferred for primitive data types, not references, so how would you know what the "name" of the variable is? For example:
var customerNr="456910";
var customerNrAfterProcessing=customerNr;
getNameOfVariable(customerNrAfterProcessing);
Would it return customerNrAfterProcessing or customerNr?
However, you can imitate this behavior with objects.
var variableName = someMethodThatDeterminesVariableNameOrJustAConstantIfYouPrefer();
var myVariables={};
var myVariables[variableName]={};
myVariables[variableName].value="456910";
myVariables[variableName].variableName=variableName;
function getNameOfVariable(someVariable){
return someVariable.variableName;
}
getNameOfVariable(myVariables[variableName]);
Obviously, this amounts to a lot more work than just using the variableName variable directly, but it could be necessary in some more complicated situations.
See working with objects in JS reference