使用Underscore.js过滤和合并json

Question

I have a use case where I need to use underscore.js to filter a JSON. For example

{"test":{
{ key: 1,country:USA,product:A,price:200}
{key: 1,country:USA,product:B,price:200}
{key: 1,country:UK,product:B,price:300}
}
}

I have multiple dimensions for same key. I need to get the output as follows when i filter USA

{"test":{
{ key: 1,country:USA,price:400}
}
}

and when I filter for product B

{"test":{
{ key: 1,product:B,price:500}
}
}

I'd like to implement this using underscore.js as I believe it is fast compared to pure JS options.

Answer 1

Firstly, try to use underscore _.filter to apply searching with your criteria like product or country.

Then do an aggregation based on result from filter by simply use _.each function.

Finally, you can manipulate your result in _.map function.

I posted jsfiddle link here, it might help you

jsfiddle.net/zusquang/39os1854/

I'm doing hope this help.

Answer 2

I'm assuming you have a typo and test contains an array of objects:

var filtered = JSON.parse(jsonString).test.filter(function(item) { return item.country == 'USA' });
var total = 0;

filtered.forEach(function(item) {
    total += item.price
});

Don't worry about speed, this would be a micro-optimization, which is not recommended.