Javascript: Nested JSON api request with multiple query parameters

Question

I try to make an API for my next website and I have trouble to get multiple query results with the same url in an express app.

Dummy data:

var data = [{
    articles : [{
        id : '0',
        url : 'foo',
        title : 'Foo',
        body : 'some foo bar',
        category : 'foo',
        tags : [
            'foo'
        ]
    }, {
        id : '1',
        url : 'foo-bar',
        title : 'Foo bar',
        body : 'more foo bar',
        category : 'foo',
        tags : [
            'foo', 'bar'
        ]
    }, {
        id : '2',
        url : 'foo-bar-baz',
        title : 'Foo bar baz',
        body : 'more foo bar baz',
        category : 'foo',
        tags : [
            'foo',
            'bar',
            'baz'
        ]
    }]
}, {
    users : [{
        name: 'Admin'
    }, {
        name: 'User'
    }]
}];

Router:

// Grabs articles by categories and tags
// http://127.0.0.1:3000/api/articles/category/foo/tag/bar
router.get('/articles/category/:cat/tag/:tag', function(req, res) {
  var articles = data[0].articles;
  var q = articles.filter(function (article) {
    return article.category === req.params.cat;
    return article.tags.some(function(tagId) { return tagId === req.params.tag;});
  });
  res.json(q);
});

How I can nest the results if I requesting the http://127.0.0.1:3000/api/articles/category/foo/tag/bar url? Now if I do this, tag url is ignored, only category requests have effect.

Thank You for your help!

trincot · Accepted Answer · 2016-02-13 14:02:16Z

1

You need to rewrite your return statement as follows:

return article.category === req.params.cat &&
       article.tags.some(function(tagId) {
           return tagId === req.params.tag;
       });

... using the && operator, otherwise you will only test on the first condition, never reaching the other statement.

Here is a test when request is on category 'foo' and tag 'bar':

var data =
[
  { articles:
    [
      { id: '0', url: 'audrey-hepburn', title: 'Audrey Hepburn', body: 'Nothing is impossible, the word itself says \'I\'m possible\'!', category: 'foo', tags: [ 'foo' ] },
      { id: '1', url: 'walt-disney', title: 'Walt Disney', body: 'You may not realize it when it happens, but a kick in the teeth may be the best thing in the world for you.', category: 'foo', tags: [ 'foo', 'bar' ] },
      { id: '2', url: 'unknown', title: 'Unknown', body: 'Even the greatest was once a beginner. Don\'t be afraid to take that first step.', category: 'bar', tags: [ 'foo', 'bar', 'baz' ] },
      { id: '3', url: 'neale-donald-walsch', title: 'Neale Donald Walsch', body: 'You are afraid to die, and you\'re afraid to live. What a way to exist.', category: 'bar', tags: [ 'foo', 'bar', 'baz' ] }
    ]
  },
  { users:
    [
      { name: 'Admin' },
      { name: 'User' }
    ]
  }
];

req = {params: {cat: 'foo', tag: 'bar'}};

var articles = data[0].articles;
var q = articles.filter(function (article) {
    return article.category === req.params.cat &&
           article.tags.some(function(tagId) { 
               return tagId === req.params.tag;
           });
});

document.write('<pre>', JSON.stringify(q, null, 4), '</pre>');

See how it matches the last entry.

edited Feb 13, 2016 at 14:02

answered Feb 13, 2016 at 12:40

trincot

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14 Comments

trincot Over a year ago

I think I might have misunderstood. You want to do requests like this: /articles/category/foo/tag/bar. Is that right? Could you put back the original router.get(/articles/category/:cat/tag/:tag', ... URL pattern and in the function just output res.json(req.params);. I want to make sure you see bot the category and tag in that params.

trincot Over a year ago

OK, that means the URL pattern is working correctly. Forget everything I wrote about that, I reverted my answer back to what it was before. Let me check now what else could be going wrong...

trincot Over a year ago

I updated my answer, using the data you have on github, and replaced the || operator with && which makes it required that both the cat and tag conditions are met.

Lanti Over a year ago

I beautified a little bit the api router. Thank You again your help! :) github.com/DJviolin/horgalleryNode/blob/master/routes/api.js

trincot Over a year ago

No, I meant that as you moved the article.category === req.params.cat inside the some callback function, you actually multiply the execution of that test, which will always be the same. But really, this should not have much of a performance impact. It's OK.

|

loadaverage · Accepted Answer · 2016-02-13 12:36:15Z

1

Problem is here >>

return article.category === req.params.cat;
return article.tags.some(function(tagId) { return tagId === req.params.tag;});

first return statement will stop further action within function so you need if ... else or case or helper function here

answered Feb 13, 2016 at 12:36

loadaverage

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3 Comments

Lanti Over a year ago

return article.category === req.params.cat, article.tags.some(function(tagId) { return tagId === req.params.tag;}); seems like work. Is it a good solution? EDIT: Nope. Returning every category. Tags working instead.

loadaverage Over a year ago

No, return in this case will execute all but return last statement

loadaverage Over a year ago

You can try [articles].indexOf(el) and [tags].indexOf(el) if the both are Arrays.

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