When does JS create an object wrapper for a string?











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Symbol.iterator in 'retularString' // error right-hand side of in sould be an object



Symbol.iterator in new String() // true



Does that mean JS creates object wrappers for strings only when it calls methods / or accesses corresponding properties on them like 'string'.toUppercase() / 'string'.length?






javascript javascript-objects







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    Symbol.iterator in 'retularString' // error right-hand side of in sould be an object



    Symbol.iterator in new String() // true



    Does that mean JS creates object wrappers for strings only when it calls methods / or accesses corresponding properties on them like 'string'.toUppercase() / 'string'.length?






    javascript javascript-objects







    share|improve this question


























      up vote
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      down vote

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      up vote
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      Symbol.iterator in 'retularString' // error right-hand side of in sould be an object



      Symbol.iterator in new String() // true



      Does that mean JS creates object wrappers for strings only when it calls methods / or accesses corresponding properties on them like 'string'.toUppercase() / 'string'.length?






      javascript javascript-objects







      share|improve this question















      Symbol.iterator in 'retularString' // error right-hand side of in sould be an object



      Symbol.iterator in new String() // true



      Does that mean JS creates object wrappers for strings only when it calls methods / or accesses corresponding properties on them like 'string'.toUppercase() / 'string'.length?






      javascript javascript-objects




      javascript javascript-objects






      share|improve this question















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      edited Nov 13 at 7:15

























      asked Nov 13 at 7:09









      daGo

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          Does that mean JS creates object wrappers for strings only when it calls methods / or accesses corresponding properties on them like 'string'.toUppercase() / 'string'.length?




          Yes.



          When you have a string declared as var foo = 'foo' its type is the primitive string, having no properties inherently, but when you try and access a property on it, the primitive is wrapped momentarily in the String object through a process called implicit coercion.



          See this article for a full explanation of coercion in JavaScript.






          share|improve this answer

















          • 1




            Perhaps the answers to this question are a good addition: stackoverflow.com/q/17256182/10245948
            – Hero Wanders
            Nov 13 at 7:47










          • I just wanted to be sure that's wrapping does not occur upon any other circumstances.
            – daGo
            Nov 13 at 8:00











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          up vote
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          down vote



          accepted











          Does that mean JS creates object wrappers for strings only when it calls methods / or accesses corresponding properties on them like 'string'.toUppercase() / 'string'.length?




          Yes.



          When you have a string declared as var foo = 'foo' its type is the primitive string, having no properties inherently, but when you try and access a property on it, the primitive is wrapped momentarily in the String object through a process called implicit coercion.



          See this article for a full explanation of coercion in JavaScript.






          share|improve this answer

















          • 1




            Perhaps the answers to this question are a good addition: stackoverflow.com/q/17256182/10245948
            – Hero Wanders
            Nov 13 at 7:47










          • I just wanted to be sure that's wrapping does not occur upon any other circumstances.
            – daGo
            Nov 13 at 8:00















          up vote
          3
          down vote



          accepted











          Does that mean JS creates object wrappers for strings only when it calls methods / or accesses corresponding properties on them like 'string'.toUppercase() / 'string'.length?




          Yes.



          When you have a string declared as var foo = 'foo' its type is the primitive string, having no properties inherently, but when you try and access a property on it, the primitive is wrapped momentarily in the String object through a process called implicit coercion.



          See this article for a full explanation of coercion in JavaScript.






          share|improve this answer

















          • 1




            Perhaps the answers to this question are a good addition: stackoverflow.com/q/17256182/10245948
            – Hero Wanders
            Nov 13 at 7:47










          • I just wanted to be sure that's wrapping does not occur upon any other circumstances.
            – daGo
            Nov 13 at 8:00













          up vote
          3
          down vote



          accepted







          up vote
          3
          down vote



          accepted







          Does that mean JS creates object wrappers for strings only when it calls methods / or accesses corresponding properties on them like 'string'.toUppercase() / 'string'.length?




          Yes.



          When you have a string declared as var foo = 'foo' its type is the primitive string, having no properties inherently, but when you try and access a property on it, the primitive is wrapped momentarily in the String object through a process called implicit coercion.



          See this article for a full explanation of coercion in JavaScript.






          share|improve this answer













          Does that mean JS creates object wrappers for strings only when it calls methods / or accesses corresponding properties on them like 'string'.toUppercase() / 'string'.length?




          Yes.



          When you have a string declared as var foo = 'foo' its type is the primitive string, having no properties inherently, but when you try and access a property on it, the primitive is wrapped momentarily in the String object through a process called implicit coercion.



          See this article for a full explanation of coercion in JavaScript.







          share|improve this answer












          share|improve this answer



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          answered Nov 13 at 7:22









          Vulcan

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          22.4k93976








          • 1




            Perhaps the answers to this question are a good addition: stackoverflow.com/q/17256182/10245948
            – Hero Wanders
            Nov 13 at 7:47










          • I just wanted to be sure that's wrapping does not occur upon any other circumstances.
            – daGo
            Nov 13 at 8:00














          • 1




            Perhaps the answers to this question are a good addition: stackoverflow.com/q/17256182/10245948
            – Hero Wanders
            Nov 13 at 7:47










          • I just wanted to be sure that's wrapping does not occur upon any other circumstances.
            – daGo
            Nov 13 at 8:00








          1




          1




          Perhaps the answers to this question are a good addition: stackoverflow.com/q/17256182/10245948
          – Hero Wanders
          Nov 13 at 7:47




          Perhaps the answers to this question are a good addition: stackoverflow.com/q/17256182/10245948
          – Hero Wanders
          Nov 13 at 7:47












          I just wanted to be sure that's wrapping does not occur upon any other circumstances.
          – daGo
          Nov 13 at 8:00




          I just wanted to be sure that's wrapping does not occur upon any other circumstances.
          – daGo
          Nov 13 at 8:00


















           

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