1

Take the following two objects.

filterForm = {'claim_number': null, 'status': 'approved', 'patient': null, 'service_date': null} this.rows = [ { "claim_number": '6632224-3', 'patient': 'Janine Soprano', 'allowed_amount':'$100', 'service': 'medical', 'status': 'approved', 'provider': 'Sam Smith'}, { "claim_number": '3218458-0', 'patient': 'Samatha Snow', 'allowed_amount':'$1100', 'service': 'medical', 'status': 'approved', 'provider': 'John Smith'}

How can I loop through this.rows and check to see which of it's Object keys match the keys of filterForm? I've seen post about checking if an object matches another exactly, but I'm only interested in looping through the object to check which keys match.

Subsequently, once I establish which keys match how can I then check to see which values match?

Improve this question
6
  • 2
    Use Object.keys to get an array of the given objects keys.. then loop your array of objects and check each individually. Commented Dec 3, 2018 at 21:42
  • I've tried to do that, but it always returns false. Commented Dec 3, 2018 at 21:44
  • If you can show me a working example that would be greatly appreciated. Commented Dec 3, 2018 at 21:45
  • 1
    @London804 - better yet, if you post your code, we can show you where you went wrong. Commented Dec 3, 2018 at 21:46
  • What should happen if all properties of filterForm are null? What should happen if two or more fields in filterForm have values? Commented Dec 3, 2018 at 21:51

3 Answers 3

Reset to default
2

You can use Object.keys to get your filterForm keys:

let availableKeys = Object.keys(filterForm);

Then you need to loop this.rows and find all the keys contained in your above array:

this.rows.forEach(row => { let rowKeys = Object.keys(row); let matchingRowKeys = availableKeys.filter(k => rowKeys.indexOf(k) > -1); //If you then want to check if the values match matchingRowKeys.forEach(rk => { if (row[rk] === filterForm[rk]) { //matching value console.log("Found matching key/value", rk, row[rk]); } }); });

Fiddle: http://jsfiddle.net/2nw3fg0d/

Improve this answer
Sign up to request clarification or add additional context in comments.

Comments

2

Here is an simple example of how to find the matching keys. This does the following:

  1. Get the filter_form keys by using Object.keys().
  2. Create a Set of those keys for quick lookup using Set.has().
  3. Loop through the rows.
    1. For each row get the keys in the same way as described above.
    2. Use Array.filter() to filter out the keys that are present in filter_keys.

var filter_form, rows, filter_keys, result; filter_form = { 'claim_number': null, 'status': 'approved', 'patient': null, 'service_date': null }; rows = [ { 'claim_number': '6632224-3', 'patient': 'Janine Soprano', 'allowed_amount': '$100', 'service': 'medical', 'status': 'approved', 'provider': 'Sam Smith' }, { 'claim_number': '3218458-0', 'patient': 'Samatha Snow', 'allowed_amount': '$1100', 'service': 'medical', 'status': 'approved', 'provider': 'John Smith' } ]; filter_keys = new Set(Object.keys(filter_form)); result = rows.map(row => Object.keys(row).filter(key => filter_keys.has(key))); console.log(result);

This answer uses a Set instance to quickly find the keys. If you don't want to use sets replace the following parts.

filter_keys = new Set(Object.keys(filter_form)) // with filter_keys = Object.keys(filter_form) 

key => filter_keys.has(key) // with key => filter_keys.indexOf(key) !== -1

If you're not interested in mapping, but rather want to work with the matching keys in the current iteration use:

let filter_keys = new Set(Object.keys(filter_form)); rows.forEach(row => { let matching_keys = Object.keys(row).filter(key => filter_keys.has(key)); // ... });
Improve this answer

2 Comments

What's .log()? Also, this didn't seem to work my console.log for result just returns five empty arrays. I also tried the second version and matching_keys returns an empty array.
@London804 That was meant to log each row in-between. I've simplified the answer a bit by removing that part. Check if it works now, if not I'm curious which browser you're using. Your browser might not have Set support or arrow function support.
0

You can use flatMap, Array.filter() and the new Set object to get unique keys, while also keeping your code short and readable.

// Get an array of filterForm's keys const filterFormKeys = Object.keys(filterForm); // Get a flattened array of this.rows' keys const rowKeys = this.rows.flatMap(item => Object.keys(item)); // Get keys that exist in both arrays using Array.filter const existingKeys = rowKeys.filter(key => filterFormKeys.includes(key)); // Use the Set object to get unique keys out of existingKeys const uniqueExistingKeys = [...new Set(existingKeys)]; console.log(uniqueExistingKeys)

Here's a jsfiddle with an example (Open your console).

Note: You can also use filter instead of Set

const uniqueExistingKeys = existingKeys.filter((value, index) => existingKeys.indexOf(value) === index);

I chose Set because it's more concise. It's all up to you :)

Improve this answer

3 Comments

Your code is pretty clear, but I don't think I can use it because .flatMap() is experimental. I'm using Angular CLI and I get the ERROR TypeError: this.rows.flatMap is not a function
@London804 Well, if you're using lodash, there's lodash flatMap. Also, there's this comment which you can use to use Array.flatMap.
@London804 Also, it is worth noting that even though .flatMap() is experimental, it is very widely used. :)

Start asking to get answers

Find the answer to your question by asking.

Ask question

Explore related questions

See similar questions with these tags.