Check if item in array exists inside object

Question

So I have an object array that I need to check against a few variables I'm being sent. I am using underscore (plain javascript is fine too though) I have the object array looking like so -

  var o = [{
      module: "mod1",
      customUrl: [{
          "state": "name1",
          "options": ["option1", "option2", "option3"]
      }, {
          "state": "name2",
          "options": ["option1", "option2", "option3"]
      }]
  }, {
      module: "mod2",
      customUrl: [{
          "state": "name1",
          "options": ["option1", "option2", "option3"]
      }, {
          "state": "name2",
          "options": ["option1", "option2", "option3"]
      }]
  }]

I have a function where I'm being passed three vars I would like to check if the last one exists inside of the first 2. Let me show you what I mean

  test  = function (module, state, option){

  }

So what I am looking to do is, for example if I passed in

  test(mod1,name1, option2);

I would like to check if there is a module with a key of "mod1", and then inside of that object there is an object inside of custom url with a state of "name1", and if that objects options array has the value "options2" inside of it. This is some more serious traversal, I could use some help. Thanks for reading!

Answer 1

With Underscore.js it will be as simple as

function testContains(o, module, state, option) {
    return _.chain(o)
        .findWhere({module: module})
        .result('customUrl')
        .findWhere({state: state})
        .result('options')
        .contains(option)
        .value();
}

Demo: http://jsfiddle.net/3f1n32tj/

Answer 2

A plain JavaScript version:

function test(o, module, state, option) {
  return o.some(function(o) {
    return o.module == module && o.customUrl.some(function(o) {
      return o.state == state && o.options.indexOf(option) != -1;
    })
  });
}

http://jsfiddle.net/5335bp4j

Answer 3

Here's an example of how you could do this with lodash. (Note that I named your o array objects because o seemed confusing in the example.):

function test(moduleName, stateName, optionName) {
  var object = _.find(objects, function(object) { return object.module == moduleName; });
  if (object) {
    var customUrl = _.find(object.customUrl, function(customUrl) { return customUrl.state == stateName; });
    if (customUrl) {
      var option = _.find(customUrl.options, function(option) { return option == optionName; });
    }
  }

  return !!option;
}

See http://jsfiddle.net/bvaughn/53h6zoeq/

You could obviously implement the same thing with vanilla JS.

Answer 4

You can just traverse the data structure using two loops:

o.forEach(function(m) {
    if (m.module === mod1) {
        m.customUrl.forEach(function(s) {
            if (f.state === name1 &&
                f.options.indeOf(option2) >= 0) {
                // We found it (one of them)
            }
        });
    }
});

The third loop can be avoided using indexOf on the array.