Find deeply nested JSON property using lodash

Question

I have a JSON API response with the following structure

[
  {
    title: "top1",
    sections: [
      {
        section_title: "section1",
        content: [
          {
            content_title: "title1",
            content_id: "id1"
          },
          {
            content_title: "title2",
            content_id: "id2"
          }
        ]
      },
      {
        section_title: "section2",
        content: [
          {
            content_title: "title3",
            content_id: "id3"
          },
          {
            content_title: "title4",
            content_id: "id4"
          }
        ]
      }
    ]
  }, {
    title: "top2",
    sections: [...]
  },
  ...
]

I also have a small array of content identifiers arr2 = ['id2','id3']. I need to find data from an API request to find any content_id contained in arr2.

I have some working lodash code, but my approach to nested forEach is apparently not the most efficient approach:

_.forEach(response, function(top) {
  _.forEach(top.sections, function(section) {
    _.forEach(section.content, function(content) {
      _.forEach(arr2, function(id) {
        if(id === content.content_id) {
         // Do stuff
        }
      })
    })
  })
})

How can I improve this code?

Answer 1

, , lodash . , , , forEach - . , , , lodash varity javascript forEach Array find forEach ( ).

response.forEach((topItem) => {
    topItem.sections.forEach((section) => {
        section.content.forEach((content) => {
            if(arr2.find((item) => { return item === content.content_id; })){
                topItem.owned = true; section.owned = true; content.owned = true;
            }
        });
    });
});

...

Answer 2

, .

function deepWalk(collection, childKeys, iteratee) {

  // create a partial _.each with an iterator that will
  // recursively traverse properties from the `childKeys` array
  var each = _.partial(_.each, _, function(value, index) {
    // invoke iteratee callback
    iteratee(value, index);
    // only recursively iterate over properties found in childKeys
    _(value).pick(childKeys).each(each);
  });

  // invoke iteration
  each(collection);

}

deepWalk(collection, ['sections', 'content'], function(value) {
  if(_.includes(['id2', 'id3'], value.content_id)) {
    // do whatever you want here..
    console.log(value);
  }
});

var collection = [
  {
    title: "top1",
    sections: [
      {
        section_title: "section1",
        content: [
          {
            content_title: "title1",
            content_id: "id1"
          },
          {
            content_title: "title2",
            content_id: "id2"
          }
        ]
      },
      {
        section_title: "section2",
        content: [
          {
            content_title: "title3",
            content_id: "id3"
          },
          {
            content_title: "title4",
            content_id: "id4"
          }
        ]
      }
    ]
  }
];

function deepWalk(collection, childKeys, iteratee) {
  
  // create a partial _.each with an iterator that will
  // recursively traverse properties from the `childKeys` array
  var each = _.partial(_.each, _, function(value, index) {
    // invoke iteratee callback
    iteratee(value, index);
    // only recursively iterate over properties found in childKeys
    _(value).pick(childKeys).each(each);
  });
  
  // invoke iteration
  each(collection);
  
}

deepWalk(collection, ['sections', 'content'], function(value) {
  if(_.includes(['id2', 'id3'], value.content_id)) {
    // do whatever you want here..
    console.log(value);
  }
});

.as-console-wrapper { min-height: 100%; top: 0; }

<script src="https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.17.4/lodash.min.js"></script>

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