needle/haystack deep search, searches for value if it matches a key and will stop execution once found.

deepsearch-find-first.js

'use strict';

function deepsearch_find_first(needle, haystack, parent) {
  
  let iterable;

  if (Object.prototype.toString.call(haystack) === '[object Array]') {
    iterable = haystack;
  } else if (Object.prototype.toString.call(haystack) === '[object Object]') {
    iterable = Object.keys(haystack);
  } else if (needle === haystack) {
    return parent;
  } else {
    return;
  }

  for (let i = 0; i < iterable.length; i++) {
    let key = haystack.hasOwnProperty(iterable[i]) ? haystack[iterable[i]] : iterable[i];
    let found = deepsearch_find_first(needle, key, haystack);
    if (found)
      return found;
  }
  
}

var fixture = {
  a: {
    a1: 'df',
    a2: 'dlkfj',
    b: {
      c: {
        d: {
          e: {
            f: 'mouse'
          }
        }
      },
      g: [
        5,
        45,
        true,
        null,
        false,
        5643635,
        {
          a: {
            b: {
              c: {
                d: 'horse'
              }
            }
          },
          f: [
            {},
            {},
            [],
            undefined,
            {
              a: 'cat'
            }
          ]
        }
      ]
    }
  }
};

var result = deepsearch_find_first('cat', fixture);

console.log(typeof result === 'object', 'result should return object');
console.log(result.hasOwnProperty('a'), 'result should have a key');
console.log(result.a === 'cat', 'result should have cat val');

deepsearch-find-first.spec.js

var fixture = {
  a: {
    a1: 'df',
    a2: 'dlkfj',
    b: {
      c: {
        d: {
          e: {
            f: 'mouse'
          }
        }
      },
      g: [
        5,
        45,
        true,
        null,
        false,
        5643635,
        {
          a: {
            b: {
              c: {
                d: 'horse'
              }
            }
          },
          f: [
            {},
            {},
            [],
            undefined,
            {
              a: 'cat'
            }
          ]
        }
      ]
    }
  }
};

var result = deepsearch_find_first('cat', fixture);

console.log(typeof result === 'object', 'result should return object');
console.log(result.hasOwnProperty('a'), 'result should have a key');
console.log(result.a === 'cat', 'result should have cat val');