How to sum json array

How can I to sum elements of a JSON array like this, using jQuery:

"taxes": [ { "amount": 25, "currencyCode": "USD", "decimalPlaces": 0, "taxCode": "YRI" }, { "amount": 25, "currencyCode": "USD", "decimalPlaces": 0, "taxCode": "YRI" }, { "amount": 10, "currencyCode": "USD", "decimalPlaces": 0, "taxCode": "YRI" } ] 

The result should be:

totalTaxes = 60

2 Answers

Working with JSON 101

var foo = { taxes: [ { amount: 25, currencyCode: "USD", decimalPlaces: 0, taxCode: "YRI"}, { amount: 25, currencyCode: "USD", decimalPlaces: 0, taxCode: "YRI"}, { amount: 10, currencyCode: "USD", decimalPlaces: 0, taxCode: "YRI"} ] }, total = 0, //set a variable that holds our total taxes = foo.taxes, //reference the element in the "JSON" aka object literal we want i; for (i = 0; i < taxes.length; i++) { //loop through the array total += taxes[i].amount; //Do the math! } console.log(total); //display the result 

If you really must use jQuery, you can do this:

var totalTaxes = 0; $.each(taxes, function () { totalTaxes += this.amount; }); 

Or you can use the ES5 reduce function, in browsers that support it:

totalTaxes = taxes.reduce(function (sum, tax) { return sum + tax.amount; }, 0); 

Or simply use a for loop like in @epascarello's answer...