filter an array of objects by an array attribute with another array

Question

The following code does NOT return the expected results of an array with 1 item. Can someone please enlighten me about the correct syntax?

 let things = [{ Name: 'Bill', Tags: ['tall', 'dude'] }, { Name: 'Ted', Tags: ['short', 'dude'] } ]; let selectedTags = ['short', 'chick']; let filtered = things.filter((thing => thing.Tags.indexOf(selectedTags) >= 0)); console.log(filtered); 

Answer 1

You are passing Array selectedTags to includes . You need to check loop through selectedTags and check if tag is present in .Tags of object.

 let things = [{Name: 'Bill', Tags: ['tall','dude']}, {Name: 'Ted', Tags: ['short','dude']}]; console.log(things); let selectedTags = ['short','chick']; let filtered = things.filter(x => { for(let tag of selectedTags){ if(x.Tags.includes(tag)) return true; } return false; }); console.log(filtered); 

Answer 2

selectedTags is an array.

.indexOf() is wainting for a string.

You can get the string into your array by selected with index, like :

thing.Tags.indexOf(selectedTags[0])

Answer 3

So it looks like you want to filter things based on if any of thing.Tags is in selectedTags .

You would do something like this

things.filter(thing => thing.Tags.some(tag => selectedTags.includes(tag)));

This is, I think, the most expressive way to write it. Give me all things where some of thing.Tags are included in the selectedTags array.

Answer 4

If you need to filter the items that have some tag that is present on the selectedTags array, then you can go with this:

 let things = [ {Name: 'Bill', Tags: ['tall', 'dude']}, {Name: 'Ted', Tags: ['short', 'dude']} ]; let selectedTags = ['short', 'chick']; let filtered = things.filter( thing => selectedTags.some(x => thing.Tags.includes(x)) ); console.log(filtered); 

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If you need to filter the items that have all the tags present on the selectedTags array, then you can use:

 let things = [ {Name: 'Bill', Tags: ['tall', 'dude']}, {Name: 'Ted', Tags: ['short', 'dude']}, {Name: 'Test', Tags: ['short', 'chick']} ]; let selectedTags = ['short', 'chick']; let filtered = things.filter( thing => selectedTags.every(x => thing.Tags.includes(x)) ); console.log(filtered); 

 .as-console {background-color:black !important; color:lime;} .as-console-wrapper {max-height:100% !important; top:0;} 

Answer 5

You have to iterate over each things element and analyze every item in its Tags attribute array:

 let things = [{ Name: 'Bill', Tags: ['tall', 'dude'] }, { Name: 'Ted', Tags: ['short', 'dude'] } ]; let selectedTags = ['short', 'chick']; let filtered = things.filter(el => { //Use reduce on to get a count of how many matching tags return el.Tags.reduce((accum, tag) => { if (selectedTags.indexOf(tag) > -1) { accum += 1; } return accum; }, 0); }); console.log(filtered);