Update after Expected Output was added:

Question

96

Cannot read property 'concat' of undefined

rated 0 times [ 98] [ 2] / answers: 1 / hits: 17100 / 8 Years ago, wed, august 17, 2016, 12:00:00

to begin with, I have a multilevel of entities as in

country unit ----> customer reporting group ----> customers

each country unit has different customer reporting groups and each of the later has different customers

in the code the variable names are

cu ----> crg ---> customer

this is represented in a multilevel object called menuData:

menuData = {

    cu1: {

        CRG3: {

            Customer1: {},

            Customer5: {}

        },

        CRG7: {

            Customer3: {},

            Customer2: {},

            Customer7: {}

        }

    },

    cu4: {

        CRG1: {

            Customer2: {},

            Customer4: {}

        },

        CRG3: {

            Customer4: {}

        }

    }

};

what I wanted to do is to construct unique id for each level in a multilevel objects as well as in for example the ids for the customer units will be the same

cu1 and cu2 and so on

for the customer reporting groups the ids will consist of the cu + the crg as in
cu1+crg4

for the customer:

cu1+crg4+customer6;

what I did is a function called getIds

var getIds = function(menuData) {

    var ids = {};

    for (cu in menuData) {

        ids[cu] = cu;

        for (crg in menuData[cu]) {

            if (!(ids[cu] in ids)) {

                ids[cu] = {};

                ids[cu][crg] = ids[cu].concat(crg);

            } else ids[cu][crg] = ids[cu].concat(crg);

            for (customer in menuData[cu][crg]) {

                if (!ids[cu][crg]) {

                    ids[cu][crg] = {};

                    ids[cu][crg][customer] = ids[cu][crg].concat(customer);

                } else ids[cu][crg][customer] = ids[cu][crg].concat(customer);

            }

        }

    }

    console.log(ids);

    return ids;

};

the error I got is

Cannot read property 'concat' of undefined

what I have tried is that, because it says that it's undefined, I try to define it if its not already defined as in

if (!(ids[cu] in ids)) {

    ids[cu] = {};

    ids[cu][crg] = ids[cu].concat(crg);

}

if its not defined, define it and insert the value, but if its defined, only assign the value
else ids[cu][crg] = ids[cu].concat (crg );

why do I get this error? and how to get the the ids in multilevel objects ?

edit, excpected output is

ids = {

    cu1: {

        cu1+CRG3: { cu1+CRG3+Customer1:{}, cu1+CRG3+Customer5:{} },

        cu1+CRG7: { cu1+CRG7+Customer3:{}, cu1+CRG7+Customer2:{}, cu1+CRG7+Customer7:{} }

    },

    cu4: {

        cu4+CRG1: { cu4+CRG1+Customer2:{}, cu4+CRG1+Customer4:{} },

        cu4+CRG3: { cu4+CRG3+Customer4:{}}

    }

}

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cruz

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3 Years ago

answered 8 Years ago jimmieo · Accepted Answer

The Problem with your Code is that you are using Objects to store your data and Objects don´t have the Method "concat" only Arrays have the "concat" Method. Your Object must look like these to work:

 menuData = [

    "cu1": [

        "CRG3": [ "Customer1":{}, "Customer5":{} ],

        "CRG7": [ "Customer3":{}, "Customer2":{}, "Customer7":{} ]

    ],

    "cu4": [

        "CRG1": [ "Customer2":{}, "Customer4":{} ],

        "CRG3": [ "Customer4":{}]

    ]

]

Here´s a reference : MDN Array.concat()

What can be confusing in JS is that an Object Property can be accessed like an Array.

Update after Expected Output was added:

okay than i think concat is not the right solution for your Problem.

Try it with something like this:

var ids = {};



var menuData = {

    cu1: {

        CRG3: {

            Customer1: {},

            Customer5: {}

        },

        CRG7: {

            Customer3: {},

            Customer2: {},

            Customer7: {}

        }

    },

    cu4: {

        CRG1: {

            Customer2: {},

            Customer4: {}

        },

        CRG3: {

            Customer4: {}

        }

    }

};



for (propKeyLevel1 in menuData){

  ids[propKeyLevel1] = {};

  var propLevel1 = ids[propKeyLevel1];

  for(propKeyLevel2 in menuData[propKeyLevel1]){

    propLevel1[propKeyLevel1+++propKeyLevel2] = {};

    var propLevel2 = propLevel1[propKeyLevel1+++propKeyLevel2];

    

    for(propKeyLevel3 in menuData[propKeyLevel1][propKeyLevel2]){

      propLevel2[propKeyLevel1+++propKeyLevel2+++propKeyLevel3] = {};

    }

  }

  

}



console.log(ids);