Question

160

How to update an array of object in javascript

rated 0 times [ 166] [ 6] / answers: 1 / hits: 56435 / 11 Years ago, fri, july 19, 2013, 12:00:00

say I have a variable

 data=[] 



 //this variable is an array of object like 

 data = [

     {name:'a',value:'aa'},

     {name:'b',value:'bb'}

 ]



 // the data structrue can not be changed and the initial value is empty

now I want to update the data

 function updateData(){

     if(!data.length){

         data.push(arguments)

     }

     else{

         //this parts really confuse me

     }



 }

this function must accept any number of arguments,and the order of the objects in data dose not matters
update rule:

update the objects value to the arguments value if they have the same name.

add the arguments to the data if none of the object in data have the same name.

how to write this function?

 updateData([

     {name:'a',value:'aa'},

     {name:'b',value:'bb'}

 ])

 // expect data = [

           {name:'a',value:'aa'},

           {name:'b',value:'bb'}

           ]



 updateData([

     {name:'a',value:'aa'},

     {name:'b',value:'DD'},

     {name:'c',value:'cc'}

] )

 // expect data = [

           {name:'a',value:'aa'},

           {name:'b',value:'DD'},

           {name:'c',value:'cc'}

           ]

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nikokorbinm

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3 Years ago

answered 11 Years ago deanna · Accepted Answer

As Ashutosh Upadhyay suggested use a name value pair instead of an array:

var data ={};



var updateData=function(){

  var len = arguments.length,

  i=0;

  for(i=0;i<len;i++){

    data[arguments[i].name]=arguments[i].value;

  }

};

updateData(

 {name:a,value:22}, 

 {name:b,value:2}, 

 {name:c,value:3}, 

 {name:a,value:1} // the new value for a

);

for(key in data){

  if(data.hasOwnProperty(key)){

    console.log(key + = + data[key]);

  }

}

Just read your comment about the array, so if you have to have an array you can:

var data = [];

function findIndex(name){

  var i = 0;

  for(i=0;i<data.length;i++){

    if(data[i].name===name){

      return i;

    }

  }

  return i;

}

function updateData(){

  var i = 0;

  for(i=0;i<arguments.length;i++){

    data[findIndex(arguments[i].name)]=arguments[i];

  }

}

updateData(

 {name:a,value:22}, 

 {name:b,value:2}, 

 {name:c,value:3}, 

 {name:a,value:1} // the new value for a

);



console.log(data);