Convert string to variable name in JavaScript

Question

I   ve looked for solutions  but couldn   t find any that work   I have a variable called onlyVideo    onlyVideo  the string gets passed into a function  I want to set the variable onlyVideo inside the function as something  How can I do that    There are a number of variables that could be called into the function  so I need it to work dynamically  not hard coded if statements    Edit  There   s probably a better way of doing what you   re attempting to do  I asked this early on in my JavaScript adventure  Check out how JavaScript objects work   A simple intro      create JavaScript object var obj      key1   1        assign - set  key2  to 2 obj key2   2      read values obj key1     1  obj key2     2      read values with a string  same result as above    but works with special characters and spaces    and of course variables obj  key1       1  obj  key2       2      read with a variable var key1Str    key1   obj key1Str      1

User · Answer

Javascript has an eval   function for such occasions   function  varString      var myVar   eval varString                  Edit  Sorry  I think I skimmed the question too quickly   This will only get you the variable  to set it you need  function SetTo5 varString      var newValue   5    eval varString           newValue       or if using a string   function SetToString varString      var newValue    string     eval varString                 newValue             But I imagine there is a more appropriate way to accomplish what you re looking for  I don t think eval   is something you really want to use unless there s a great reason for it  eval

User · Answer

As far as eval vs  global variable solutions     I think there are advantages to each but this is really a false dichotomy  If you are paranoid of the global namespace just create a temporary namespace  amp  use the same technique   var tempNamespace       var myString    myVarProperty    tempNamespace myString    5    Pretty sure you could then access as tempNamespace myVarProperty  now 5   avoiding using window for storage   The string could also be put directly into the brackets

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If you re trying to access the property of an object  you have to start with the scope of window and go through each property of the object until you get to the one you want  Assuming that a b c has been defined somewhere else in the script  you can use the following   var values   window  var str    a b c  values split        for var i 0  i  lt  str length  i        values   values str i      This will work for getting the property of any object  no matter how deep it is

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It can be done like this   x000D   x000D   function X  Y    x000D     x000D       X is the local name of the  class  x000D       Doo is default value if param X is empty x000D    var X    typeof X     string     X   Doo   x000D    var Y    typeof Y     string     Y   doo   x000D     x000D       this refers to the local X defined above x000D    this X    function doo    x000D         object variable x000D      this doo   doo     doo it   x000D      x000D       prototypal inheritance for methods x000D       defined by another x000D    this X  prototype Y    function     x000D      return this doo     doo   x000D       x000D     x000D       make X global x000D    window X    this X   x000D     Dooa    dooa        give the names here x000D   x000D     test x000D  doo   new Dooa  abc    x000D  doo2   new Dooa  def    x000D  console log doo dooa     x000D  console log doo2 dooa     x000D   x000D   x000D

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let me make it more clear function changeStringToVariable variable  value   window variable  value   changeStringToVariable  quot name quot    quot john doe quot    console log name     this outputs  john doe let file  quot newFile quot   changeStringToVariable file   quot text file quot    console log newFile     this outputs  text file

User · Answer

The window  variableName   method ONLY works if the variable is defined in the global scope   The correct answer is  Refactor    If you can provide an  Object  context then a possible general solution exists  but there are some variables which no global function could resolve based on the scope of the variable    function        var findMe    no way

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var myString    echoHello    window myString    function         alert  Hello        echoHello      Say no to the evil eval  Example here  https   jsfiddle net Shaz WmA8t

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You can access the window object as an associative array and set it that way  window  onlyVideo      TEST   document write onlyVideo

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The following code makes it easy to refer to each of your DIVs and other HTML elements in JavaScript  This code should be included just before the  tag  so that all of the HTML elements have been seen  It should be followed by your JavaScript code      For each element with an id  example   MyDIV   in the body  create a variable    for easy reference  An example is below  var D document  var id        All ID elements var els document body getElementsByTagName       for  var i   0  i  lt  els length  i              thisid   els i  id      if   thisid          continue      val D getElementById thisid       id thisid  val            Usage  id MyDIV innerHTML  hello

User · Answer

If it s a global variable then window variableName  or in your case window  onlyVideo   should do the trick

User · Answer

You can do like this   x000D   x000D  var name    foo   x000D  var value    Hello foos   x000D  eval  var   name        value        x000D  alert foo   x000D   x000D   x000D

[javascript] Convert string to variable name in JavaScript

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