Odtnhj

I try to write a function in JavaScript which filter an array by a selected property (an value).

But it works for 2 level only I do not understand what do I missing.

The data I want to filter:

 var data = [

 
 name: "john_pc",
 children: [
 
 name: "sabrina_pc",
 children: [
 
 name: "sabrina_pc"
 ,
 
 name: "john_pc"
 
 ]
 ,
 
 name: "john_pc"
 
 ]
 ,

 
 name: "sabrina_pc"
 
]

The childrenFilter funciton :

const childrenFilter = (childrenData, filters) => 
 let filteredData = childrenData.filter(item => 
 for (var property in filters) 
 var optionalValues = filters[property];
 var value = item[property];
 if (item.children) 
 item.children = childrenFilter(item.children, filters);
 
 let hasValue = value == optionalValues;
 if (hasValue) 
 return true;
 
 return false;
 
 return false;
 , this);
 return filteredData;

Calling the function:

As you can see the 'childrenFilter' get an object which the key is property in the data and the key is value I want to keep.

let result = childrenFilter(data,
"name": "a1"
);
console.log(JSON.stringify(result, null, 2))


The wanted result :

 [
 
 "name": "john_pc",
 "children": [
 
 "name": "sabrina_pc",
 "children": [
 
 "name": "john_pc"
 
 ]
 ,
 
 "name": "john_pc"
 
 ]
 
]

Your filter function does not take into account whether or not children elements match the pattern, therefore even though some child elements of the object match the pattern, the object itself is being filtered out.

Here is the explanation:

 
 name: "a2", // does not match filter name:'a1 so is removed alongside child objects
 children: [ // gets removed with parent object
 
 name: "a2"
 ,
 
 name: "a1" 
 
 ]
 

This should produce the desired output:

 const childrenFilter = (childrenData, filters) => 
 let filteredData = childrenData.filter(item => 
 for (var property in filters) item.children.length) // include item when children mathes the pattern
 return true;
 
 return false;
 
 return false;
 , this);
 return filteredData;
 

You could build new array for each step of filtering, beginning from the leaves and check if this contains the wanted value.

This approach generates new objects and does not mutate the original data.

function filter(array, filters) 
 return array.reduce((r, o) => , filters);
 return children , undefined);


var data = [ name: "a1", children: [ name: "a2", children: [ name: "a2" , name: "a1" ] , name: "a1" ] , name: "b1" ];
 
console.log(filter(data, name: "a1" ));

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