Filter an array in Javascript based on multiple conditions

Question

Filter an array in Javascript based on multiple conditions

I am working with an array that looks like this:

var arr = 
[
    {
        "id":3,
        "first_name":"Laila",
        "last_name":"McCaine",
        "gender":"female",      
        "populations":[{"population_name":"Heart failure"}, {"population_name":"AMI"}],
        "score": 55.0
    },
    {
        "id":5,     
        "first_name":"Riva",
        "last_name":"Rontgen",
        "gender":"female",
        "populations":[{"population_name":"Pnumonia"}],
        "score": 85.0
    },
    {
        "id":8,
        "first_name":"Emily",   
        "last_name":"Rosewood",
        "gender":"female",  
        "populations":[],
        "score": 25.0
    }
];

Additionally, I have the following variables defined:

var score='';
var population='';
var status = '';

Now, I need to use the filter function on the array with multiple conditions such as Find records where the score is less than 40, status equals 1, and population_name is "heart failure".

The challenge here is that these three variables are dynamic, and the filter should only be applied if their values are not empty.

How can I achieve this?

javascript arrays

Answer 1

Answer №1

Here's an example of how you could write this:

arr.filter(function(element) {
    var valid = true;

    if (grade !== '') {
        valid = element.grade < grade;
    }

    if (valid && population !== '') {
        // check population
        valid = element.populations.map(function() {return element.population_name;}).indexOf(population) > -1;
    }

    if (valid && status !== '') {
        // check status
    }

    return valid;
});

Answer 2

Here's an example of how you could write this:

arr.filter(function(element) {
    var valid = true;

    if (grade !== '') {
        valid = element.grade < grade;
    }

    if (valid && population !== '') {
        // check population
        valid = element.populations.map(function() {return element.population_name;}).indexOf(population) > -1;
    }

    if (valid && status !== '') {
        // check status
    }

    return valid;
});

Answer 3

Answer №2

var data = 
[
    {
        "id":3,
        "status": 1,
        "first_name":"Laila",
        "last_name":"McCaine",
        "gender":"female",      
        "populations":[{"population_name":"Heart failure"}, {"population_name":"AMI"}],
        "score": 55.0
    },
    {
        "id":5,   
        "status": 1,
        "first_name":"Riva",
        "last_name":"Rontgen",
        "gender":"female",
        "populations":[{"population_name":"Pneumonia"}],
        "score": 85.0
    },
    {
        "id":8,
        "status": 0,
        "first_name":"Emily",   
        "last_name":"Rosewood",
        "gender":"female",  
        "populations":[],
        "score": 25.0
    }
];

function filterData( data ){
  return data.filter(function( entry ){
    return entry.score > 40 && entry.status && (entry.populations.filter(function( population ){
      return population.population_name == 'Heart failure';
    })).length;
  });
}

console.log( filterData( data ) );

<script src="http://codepen.io/synthet1c/pen/WrQapG.js"></script>

Answer 4

var data = 
[
    {
        "id":3,
        "status": 1,
        "first_name":"Laila",
        "last_name":"McCaine",
        "gender":"female",      
        "populations":[{"population_name":"Heart failure"}, {"population_name":"AMI"}],
        "score": 55.0
    },
    {
        "id":5,   
        "status": 1,
        "first_name":"Riva",
        "last_name":"Rontgen",
        "gender":"female",
        "populations":[{"population_name":"Pneumonia"}],
        "score": 85.0
    },
    {
        "id":8,
        "status": 0,
        "first_name":"Emily",   
        "last_name":"Rosewood",
        "gender":"female",  
        "populations":[],
        "score": 25.0
    }
];

function filterData( data ){
  return data.filter(function( entry ){
    return entry.score > 40 && entry.status && (entry.populations.filter(function( population ){
      return population.population_name == 'Heart failure';
    })).length;
  });
}

console.log( filterData( data ) );

<script src="http://codepen.io/synthet1c/pen/WrQapG.js"></script>

Filter an array in Javascript based on multiple conditions

Answer №1

Answer №2

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