我可以在 JavaScript 中使用变量作为变量名吗？

Question

I am trying to use a variable as another variables name. For example, I have the following:

var dynamicname = 'name1_'

And I am trying to set it as the name of a new variable like this:

dynamicname + '2' = 'myvalue'

This obviously isn't working but is there a way to achieve this? Would eval be suitable?

Answer 1

Slightly off, but a possible answer to this using objects can be something along the lines of:

const obj = {
    [ dynamicNameVar + '2' ]: ...
}

Or, for the old-school folks,

var obj = {};
obj[dynamicNameVar + '2'] = ...

I hope this helps! :)

Answer 2

As mentioned in the comments, you should never do this.

But if you want to do this:

var name ="name1_";

// declare a new var as name1_test and set it to 'TestWorked'.
eval("var "+name+"test = 'TestWorked'");

// prints value of name1_test ('TestWorked')
console.log(name1_test);

Answer 3

For just keeping an indicator/flag for a seen video, you could use Set or if you need more stored information, take a Map instead of using dynamically created variables where you still need to create an accessor for the variable as well.

 var seen = new Set; console.log(seen.has('foo')); // false; seen.add('foo'); console.log(seen.has('foo')); // true; 

Answer 4

To my knowledge, this is the best method.

 window["varname"]=32; console.log(varname)

Answer 5

As others said, this is a bad practice and you should use objects. But if anyone really needs to do this for some reason, the right way to do is to use the window object, instead of eval. In your case it would be:

var dynamicname = 'name1_'
window[dynamicname + '2'] = 'myvalue'

You can do alert(name1_2) and it would show "myvalue".