How to get json elements with javascript

Question

I got this little json file:

 {
 "description": {
 "is_a": "AnnotationProperty",
 "labelEN": "description",
 "labelPT": "descrição"
 },
 "relevance": {
 "is_a": "AnnotationProperty",
 "domain": "Indicator",
 "labelEN": "relevance",
 "labelPT": "relevância"
 },
 "title": {
 "is_a": "AnnotationProperty",
 "labelPT": "título",
 "labelEN": "title",
 "range": "Literal"
 }
}

I need to build a tree looking for the "is_a" field and the name before this field. Once I got these two fields, I can insert the child one on the tree in the right place.

So, using javascript, how can I get the name and the field "is_a" of each one?

I would like to have a loop statement that gives me all the names and "is_a" fields, for example, first time it gives me "description" and "AnnotationProperty" and the second iteration it gives me "relevance" and "AnnotationProperty", etc.

Thanks.

• Uzbekjon: It is not json, it's yaml file!
• Pedro Henrique Calixto: I'm so sorry. I put the wrong one. Editing...
• trincot: Please give a sample output you are expecting.
• Pedro Henrique Calixto: Sorry again. Edited.
• Pedro Henrique Calixto: Did it, trincot. Thanks.

Answer 1

You can list the names with their is_a property values like this:

Object.keys(data).forEach(function (name) {
 if (data[name].is_a) console.log(name + ' is a ' + data[name].is_a);
});

In a snippet:

var data = {
 "description": {
 "is_a": "AnnotationProperty",
 "labelEN": "description",
 "labelPT": "descrição"
 },
 "relevance": {
 "is_a": "AnnotationProperty",
 "domain": "Indicator",
 "labelEN": "relevance",
 "labelPT": "relevância"
 },
 "title": {
 "is_a": "AnnotationProperty",
 "labelPT": "título",
 "labelEN": "title",
 "range": "Literal"
 }
};
// collect name & is_a
result = [];
Object.keys(data).forEach(function (name) {
 if (data[name].is_a) result.push(name + ' is a ' + data[name].is_a);
});
// output in snippet
document.write(result.join('<br>'));

• Pedro Henrique Calixto: Thank yu so much!!! :D And just to know, is it possible to have a tree in js like it is in java or C, etc...? I'm asking this because it's my first time using js or json...
• trincot: There are no native tree classes in Javascript, but you can implement it by nesting arrays and objects. There is a lot on the subject.
• Pedro Henrique Calixto: Done :D let me ask you...do you know how to convert the yaml file into json in a js function? And save it in a js variable like you did in our example. Thanks :D
• trincot: It should be possible, but maybe it is better to ask a new question about that.

Answer 2

If your JSON string was valid, you could have parsed it into javascript object using JSON.parse() function.

And, if you want to iterate through an object, use built-in for in loop:

var json = {a:1, b:2, c:3};
for (var key in json) {
 // key
 // json[key] = {is_a: 'xxx', ...}
 // json[key][is_a]
}