根据条件 javascript 将键值对附加到字典数组

Question

I have an array of dictionaries

var nodes =
{
A: {'name' : 'A'},
B:{'name' : 'B'},
C:{'name' : 'C'},
D:{'name' : 'D'}
E:{'name' : 'E'}}

and

another array

var X_Group = ['A', 'B'];

I need to iterate through each of the dictionary elements and append group key with value X to them if it is present in the array X_Group and Y otherwise. ie.

var nodes =
{
A: {'name' : 'A' , group :'X'},
B:{'name' : 'B', group :'X'},
C:{'name' : 'C', group :'Y'},
D:{'name' : 'D', group :'Y'},
E:{'name' : 'E', group :'Y'}
}

I have tried:

  for (var key in nodes){
    if (key in X_Group)
      nodes[key].group = 'X';
else 
      nodes[key].group = 'Y';
  }

But it does not work. Any suggestions  on how to fix the issue?

Answer 1

You cannot use 'in' to check if a value is in an array. Use indexOf instead, which will return the index of the element, or -1.

Use this condition:

  if(X_Group.indexOf(nodes[key].name)!==-1)

Answer 2

Assuming nodes is an Object rather than array, and X_Group is an array, you may:

• rebuild your nodes array, using Object.assign()
• pass to Object.assign() (as its second parameter) spread array ( Array.prototype.map() ) of nodes key-value pairs, appended with group property, having 'X' / 'Y' value based on whether it is found (with Array.prototype.includes() ) within X_Group

 const nodes = {A:{'name':'A'},B:{'name':'B'},C:{'name':'C'},D:{'name':'D'},E:{'name':'E'}}, X_Group = ['A', 'B'], result = Object.assign( {}, ...Object.keys(nodes).map(key => ({[key]: {...nodes[key], group: X_Group.includes(nodes[key].name)? 'X': 'Y' }}))) console.log(result)

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