Why does map() get 2 arguments in this case?












1















Could you help me, please, I can't understand why there are 2 arguments in the map()



Children.map(this.props.children, child =>              

        <button>{child} </button>


I supposed that this construction should work 



Children.map(child =>           

        <button>{child} </button>


But it doesn't.






javascript reactjs dictionary children







share|improve this question




















  • 1





    That syntax doesn't look valid. More than one argument requires parentheses.

    – CertainPerformance
    Nov 15 '18 at 12:33






  • 1





    Is this using React.Children? Don't confuse it with the array method map.

    – Tholle
    Nov 15 '18 at 12:34






  • 2





    first argument is what to map over and second is the mapping function

    – ashish singh
    Nov 15 '18 at 12:35











  • Yeah, that React.Children

    – Roman Tselenko
    Nov 15 '18 at 12:35
















1















Could you help me, please, I can't understand why there are 2 arguments in the map()



Children.map(this.props.children, child =>              

        <button>{child} </button>


I supposed that this construction should work 



Children.map(child =>           

        <button>{child} </button>


But it doesn't.






javascript reactjs dictionary children







share|improve this question




















  • 1





    That syntax doesn't look valid. More than one argument requires parentheses.

    – CertainPerformance
    Nov 15 '18 at 12:33






  • 1





    Is this using React.Children? Don't confuse it with the array method map.

    – Tholle
    Nov 15 '18 at 12:34






  • 2





    first argument is what to map over and second is the mapping function

    – ashish singh
    Nov 15 '18 at 12:35











  • Yeah, that React.Children

    – Roman Tselenko
    Nov 15 '18 at 12:35














1












1








1








Could you help me, please, I can't understand why there are 2 arguments in the map()



Children.map(this.props.children, child =>              

        <button>{child} </button>


I supposed that this construction should work 



Children.map(child =>           

        <button>{child} </button>


But it doesn't.






javascript reactjs dictionary children







share|improve this question
















Could you help me, please, I can't understand why there are 2 arguments in the map()



Children.map(this.props.children, child =>              

        <button>{child} </button>


I supposed that this construction should work 



Children.map(child =>           

        <button>{child} </button>


But it doesn't.






javascript reactjs dictionary children




javascript reactjs dictionary children






share|improve this question















share|improve this question













share|improve this question




share|improve this question








edited Nov 15 '18 at 12:36







Roman Tselenko

















asked Nov 15 '18 at 12:32









Roman TselenkoRoman Tselenko

386




386








  • 1





    That syntax doesn't look valid. More than one argument requires parentheses.

    – CertainPerformance
    Nov 15 '18 at 12:33






  • 1





    Is this using React.Children? Don't confuse it with the array method map.

    – Tholle
    Nov 15 '18 at 12:34






  • 2





    first argument is what to map over and second is the mapping function

    – ashish singh
    Nov 15 '18 at 12:35











  • Yeah, that React.Children

    – Roman Tselenko
    Nov 15 '18 at 12:35














  • 1





    That syntax doesn't look valid. More than one argument requires parentheses.

    – CertainPerformance
    Nov 15 '18 at 12:33






  • 1





    Is this using React.Children? Don't confuse it with the array method map.

    – Tholle
    Nov 15 '18 at 12:34






  • 2





    first argument is what to map over and second is the mapping function

    – ashish singh
    Nov 15 '18 at 12:35











  • Yeah, that React.Children

    – Roman Tselenko
    Nov 15 '18 at 12:35








1




1





That syntax doesn't look valid. More than one argument requires parentheses.

– CertainPerformance
Nov 15 '18 at 12:33





That syntax doesn't look valid. More than one argument requires parentheses.

– CertainPerformance
Nov 15 '18 at 12:33




1




1





Is this using React.Children? Don't confuse it with the array method map.

– Tholle
Nov 15 '18 at 12:34





Is this using React.Children? Don't confuse it with the array method map.

– Tholle
Nov 15 '18 at 12:34




2




2





first argument is what to map over and second is the mapping function

– ashish singh
Nov 15 '18 at 12:35





first argument is what to map over and second is the mapping function

– ashish singh
Nov 15 '18 at 12:35













Yeah, that React.Children

– Roman Tselenko
Nov 15 '18 at 12:35





Yeah, that React.Children

– Roman Tselenko
Nov 15 '18 at 12:35












1 Answer
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React.Children map API takes the first argument as the children array to iterate on and the second argument as the callback function that is called with each of the iterated children



Unlike the normal map which is the prototype of the Array constructor function, in the above case map is a function defined for the Children Object and needs to be passed with the array it has to iterate on






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    1 Answer
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    1 Answer
    1






    active

    oldest

    votes









    active

    oldest

    votes






    active

    oldest

    votes









    3














    React.Children map API takes the first argument as the children array to iterate on and the second argument as the callback function that is called with each of the iterated children



    Unlike the normal map which is the prototype of the Array constructor function, in the above case map is a function defined for the Children Object and needs to be passed with the array it has to iterate on






    share|improve this answer




























      3














      React.Children map API takes the first argument as the children array to iterate on and the second argument as the callback function that is called with each of the iterated children



      Unlike the normal map which is the prototype of the Array constructor function, in the above case map is a function defined for the Children Object and needs to be passed with the array it has to iterate on






      share|improve this answer


























        3












        3








        3







        React.Children map API takes the first argument as the children array to iterate on and the second argument as the callback function that is called with each of the iterated children



        Unlike the normal map which is the prototype of the Array constructor function, in the above case map is a function defined for the Children Object and needs to be passed with the array it has to iterate on






        share|improve this answer













        React.Children map API takes the first argument as the children array to iterate on and the second argument as the callback function that is called with each of the iterated children



        Unlike the normal map which is the prototype of the Array constructor function, in the above case map is a function defined for the Children Object and needs to be passed with the array it has to iterate on







        share|improve this answer












        share|improve this answer



        share|improve this answer










        answered Nov 15 '18 at 12:35









        Shubham KhatriShubham Khatri

        89.9k15111149




        89.9k15111149
































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