Searching JSON array using another JSON array node js

Question

I'm trying to filter a JSON array using another JSON array criteria that I have using (filter).

Here is my code:

function filterArray(object, criteria){
    return object.filter(function(obj){
        for(var i=0;i<criteria.length;i++){
            let criteriaEle = criteria[i];
            return Object.keys(criteriaEle).forEach(function(key){
                if(obj[key] == criteriaEle[key]){
                    return obj;
                }
            })
        }
    })
}

For example:

object = [{type:1,company:1,color:0,name:a},{type:2,company:1,color:0,name:b},{type:1,company:3,color:0,name:c},{type:4,company:1,color:0,name:d},{type:1,company:1,color:1,name:e}]

criteria = [{type:1,company:1,color:0},{type:1,company:1,color:1}]

So if I give these two arrays to the function it should return

obj = [{{type:1,company:1,color:0,name:a},{type:1,company:1,color:1,name:e}}]

I'm not sure where am I going wrong in this. Please help.

Update: Also, I do not want to use obj.type or obj.company or object.color as parameters to search as I want to make my code maintainable and do not want to come and update it later if in future more criteria's are added.

How about using underscore.js? You can use the where function here. :) — Hannah May
– Hannah May, Commented Oct 4, 2017 at 2:50
@HannahMay It does not allow you to use logical OR in the statements. — Anurag Bhardwaj
– Anurag Bhardwaj, Commented Oct 4, 2017 at 2:55

Neeraj Sharma · Accepted Answer · 2017-10-04 04:22:47Z

3

const data = [{type:1,company:1,color:0,name:'a'},{type:2,company:1,color:0,name:'b'},{type:1,company:3,color:0,name:'c'},{type:4,company:1,color:0,name:'d'},{type:1,company:1,color:1,name:'e'}];

const criteria = [{type:1,company:1,color:0},{type:1,company:1,color:1}];

function checkCriteria(obj) {
  return criteria.some(criterion => {
    for (const key in criterion) {
      if (criterion[key] !== obj[key]) {
        return false;
      }
    }
    return true;
  });
}

const filtered = data.filter(checkCriteria);

console.log('Filtered array: ', filtered);

Here is one solution.

Here are some references

Array.some Array.filter

Based on the comment, adding another snippet to explain the concept of closures.

const data = [{type:1,company:1,color:0,name:'a'},{type:2,company:1,color:0,name:'b'},{type:1,company:3,color:0,name:'c'},{type:4,company:1,color:0,name:'d'},{type:1,company:1,color:1,name:'e'}];

function createCriteriaValidationFunction(criteria) {
  return function checkCriteria(obj) {
    return criteria.some(criterion => {
      for (const key in criterion) {
        if (criterion[key] !== obj[key]) {
          return false;
        }
      }
      return true;
    });
  }
}

const criteria = [{type:1,company:1,color:0},{type:1,company:1,color:1}];

const filtered = data.filter(createCriteriaValidationFunction(criteria));

console.log('Filtered array: ', filtered);

It's the same concept as before, however, criteria was defined in the file. This time, criteria can be defined outside and can be passed in to the function. The trick is to create the checkCriteria function on the fly with criteria passed in and available in the closure. In both cases, criteria variable is available in the scope in which checkCriteria is executed.

edited Oct 4, 2017 at 4:22

answered Oct 4, 2017 at 2:46

Neeraj Sharma

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4 Comments

Anurag Bhardwaj Over a year ago

Sorry I missed to write that I want my code to me configurable from a config. So I do not want to do "obj.type" or "obj.company" as it makes it difficult for me to maintain.

Neeraj Sharma Over a year ago

@AnuragBhardwaj Updated the solution.

Anurag Bhardwaj Over a year ago

I'm new to Array.filter and trying to understand that if I have to pass criteria object from data.filter(checkCriteria), to the function checkCriteria(obj), how do I do that?

Neeraj Sharma Over a year ago

@AnuragBhardwaj You cannot change the signature of the function which is passed in to Array.filter, however, you can create the function on the fly and chose what's part of the closure of that function. I updated the answer with another snippet doing exactly that. Note that this time, I'm not passing the function to Array.filter, but executing a function which returns a function.

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