在任意深度的嵌套数组中查找值

Question

Currently refactoring some javascript (ES6) logic, I've come across a scenario where I need to search an nested array of arbitrary depth to find certain elements, check with a helper function, and set a boolean based on the results of the helper.

let hit_possibilities = ["CASE1", "CASE2"];
let target =
    [
        "cat",
        "dog",
        [
            "CASE1",
            [
                "dad",
                "CASE2"
            ],
            "mom"
        ],
        "pam"
    ]

The above variables represent both aforementioned arrays.

I need a function that take in both a target array (which can be of any depth and any object order) and a hit_possibilities array to check if any of the elements in hit_possibilities exists in the target array. If the function hits an element that is in the hit_possibilities, it calls another function that returns true or false (contents not relevant, just an already written helper). If false is returned, the function breaks immediately, returning false. If true is returned, the function continues down the array; if arriving at no circumstance of a false return, the function return true.

Answer 1

Here's an iterative (non-stack overflow) solution that runs a depth-first search on the structure. Note that I used a set for fast lookups:

 let hitPossibilities = ["CASE1", "CASE2"]; let target = [ "cat", "dog", [ "CASE1", [ "dad", "CASE2" ], "mom" ], "pam" ]; const helper = e => false; // stub const search = (needles, haystack) => { const set = new Set(needles); const stack = [haystack]; while (stack.length) { const curr = stack.pop(); for (let i = 0; i < curr.length; i++) { if (Array.isArray(curr[i])) { stack.push(curr[i]); } else if (set.has(curr[i]) && !helper(curr[i])) { return false; } } } return true; }; console.log(search(hitPossibilities, target)); console.log(search(["FOO", "BAR"], target)); 

Answer 2

As an alternative to @ggorlen, but with recursion method it would look something like this:

let hitPossibilities = ["CASE1", "CASE2"];
let target =
    [
        "cat",
        "dog",
        [
            "CASE1",
            [
                "dad",
                "CASE2"
            ],
            "mom"
        ],
        "pam"
    ]

function search(target, hit) {
  for (let i = 0; i < target.length; ++i) {
    currTarget = target[i];

    if(Array.isArray(currTarget)) {
       if(!search(currTarget, hit)){
         return false;
       }
    } else {
      for(let j = 0; j < hit.length; ++j) {
        let currHit = hit[j];

        if(currTarget === currHit) {
          if(!isValid()) {
            return false;
          }
        }
      }
    }
  }
  return true;
}

// Your function here...
function isValid() {
  return true; // put false to test the differet output.
}

console.log(search(target, hitPossibilities));