I got an array (as result of a mongoDB query) with some elements like this:
{
"_id": "ExxTDXJSwvRbLdtpg",
"content": [
{
"content": "First paragraph",
"language":"en",
"timestamp":1483978498
},
{
"content": "Erster Abschnitt",
"language":"de",
"timestamp":1483978498
}
]
}
But I need to get just a single content field for each data array element, which should be selected by the language. So the result should be (assuming selecting the english content):
{
"_id": "ExxTDXJSwvRbLdtpg",
"content": "First paragraph"
}
instead of getting all the content data...
I tried to do it with find(c => c.language === 'en), but I don't know how to use this for all elements of the data array. Maybe it is also possible to get the data directly as a mongodb query??
You could iterate the array and replace the value inside.
var array = [{ _id: "ExxTDXJSwvRbLdtpg", content: [{ content: "First paragraph", language: "en", timestamp: 1483978498 }, { content: "Erster Abschnitt", language: "de", timestamp: 1483978498 }] }];
array.forEach(a => a.content = a.content.find(c => c.language === 'en').content);
console.log(array);Version with check for content
var array = [{ _id: "ExxTDXJSwvRbLdtpg", content: [{ content: "First paragraph", language: "en", timestamp: 1483978498 }, { content: "Erster Abschnitt", language: "de", timestamp: 1483978498 }] }, { _id: "no_content" }, { _id: "no_english_translation", content: [{ content: "Premier lot", language: "fr", timestamp: 1483978498 }, { content: "Erster Abschnitt", language: "de", timestamp: 1483978498 }] }];
array.forEach(function (a) {
var language;
if (Array.isArray(a.content)) {
language = a.content.find(c => c.language === 'en');
if (language) {
a.content = language.content;
} else {
delete a.content;
}
}
});
console.log(array);Given that _id and language are input variables, then you could use this aggregate command to get the expected result:
db.collection.aggregate([{
$match: {
_id: _id,
}
}, {
$unwind: '$content'
}, {
$match: {
'content.language': language,
}
}, {
$project: {
_id: 1,
content: '$content.content'
}
}])
var aobjs = [{
"_id": "ExxTDXJSwvRbLdtpg",
"content": [
{
"content": "First paragraph",
"language":"en",
"timestamp":1483978498
},
{
"content": "Erster Abschnitt",
"language":"de",
"timestamp":1483978498
}
]
}];
var result = aobjs.map(o => ({ id: o._id, content: o.content.find(c => c.language === 'en').content }));
This returns an object for each with just id and content. In this example, result would be:
[ { id: 'ExxTDXJSwvRbLdtpg', content: 'First paragraph' } ]