Filtering nested arrays based on multiple values

Question

I have a nested array that looks like this:

var nested_array = [
  ["18081163__,0,0.15,15238", "0", "0.15", "Somerset", "Local", "Norfolk Road"], 
  ["18081165__,0.7,0.25,15239", "0", "0.15", "Somerset", "State", "Norfolk Road"], 
  ["18081153__,0.1,0.25,15240", "0.1", "0.25", "Cumberland", "Local", "Potter Terrace"], 
  ["18081164__,1.1,2.25,15241", "1.1", "2.25", "Cumberland", "State", "Jones Street"]
]

In each subarray, index 3 = county, index 4 = road_type, and index 5 = road_name. In my application, the user must choose the road_name. I created a simple function that takes on value and returns an nested array with subarrays that contain that value:

function array_parser(old_array, key_word) {
    let new_array = [];
    for (let i = 0; i < old_array.length; i++) {
        if (old_array[i].includes(key_word)) {
            new_array.push(old_array[i]);
        }
    }
    return new_array;
}

This works well for a single value, but I want the user to be able to also choose the county and road_type optionally. If they do, I want to be a filter and return an array based on a list/array of values:

 key_words = ["Somerset", "Norfolk Road"]

or

key_words = ["Somerset", "Local", "Norfolk Road"]

How can this be achieved?

Quick question, do these keywords not have constraints? What if there's really a road that contains the same name as the state? Will that also be a valid inclusion in the parsed array? — ryeballar
– ryeballar, Commented May 14, 2021 at 15:03
So, for road_type (index 4) those are based on a limited dropdown or choices: [State, Local, Interstate, Other]. The road_names (index 5) will all have Road, Street, Lane, etc...or will be like US-95 or something, so even if the road name is "State Street", and the road type is "State", I don't think that would be an issue (although maybe I'm wrong. — gwydion93
– gwydion93, Commented May 14, 2021 at 15:12

ryeballar · Accepted Answer · 2021-05-14 15:27:16Z

You can create a function that accepts the keywords array and the array that requires the comparison criteria.
- It should be able to iterate over each keyword using Array#every wherein the predicate callback function uses Array#includes for the compared array against each of the iterated keyword.
You can modify the array_parser function to accept an array of nested arrays and an array of keywords.
- You can use Array#filter wherein the predicate callback function will use the matcher function created previously to match the keyword criteria.

function matcher(array1, array2) {
  return array1.every(value => array2.includes(value));
}

function array_parser(array, keywords) {
  return array.filter(values => matcher(keywords, values));
}

var nested_array = [
  ["18081163__,0,0.15,15238", "0", "0.15", "Somerset", "Local", "Norfolk Road"],
  ["18081165__,0.7,0.25,15239", "0", "0.15", "Somerset", "State", "Norfolk Road"],
  ["18081153__,0.1,0.25,15240", "0.1", "0.25", "Cumberland", "Local", "Potter Terrace"],
  ["18081164__,1.1,2.25,15241", "1.1", "2.25", "Cumberland", "State", "Jones Street"]
];

function matcher(array1, array2) {
  return array1.every(value => array2.includes(value));
}

function array_parser(array, keywords) {
  return array.filter(values => matcher(keywords, values));
}

let keywords = ["Somerset", "Norfolk Road"];
console.log('keywords =', keywords);
console.log(array_parser(nested_array, keywords));


keywords = [ "Somerset", "Local", "Norfolk Road"];
console.log('keywords =', keywords);
console.log(array_parser(nested_array, keywords));

.as-console-wrapper{top: 0; max-height: unset !important;};

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