Javascript: How to get numbers out of a JavaScript object?

Question

data = [ RowDataPacket { test: '12312311' },
    RowDataPacket { test: '12312312' },
    RowDataPacket { test: '12312313' } ]

I would like to get the numbers from this object into an array in Javascript. I already tried it with .split(/(\d+)/); but I get this error in Chrome:

Uncaught TypeError: data.split is not a function.

How can I extract the numbers?

It seems you mix JavaScript Object and JSON here. What you have there is already a JS object and no JSON — yunzen, Dec 03 '18 at 15:01
In order for split to work `data` would need to be a string. But really no point in changing an Object to a string to do split on it. — khollenbeck, Dec 03 '18 at 15:05

score 6 · Accepted Answer · answered Dec 03 '18 at 15:06

Your attempt will not work because .split() is a string method - it's used for breaking up a string into an array. You already have an array. JSON seems to be irrelevant here, as what you've shared is not JSON.

You can use Array.map() to mutate each member of an array. You want to get each member's test value, and parse it.

var data = [ { test: '12312311' }, { test: '12312312' }, { test: '12312313' } ];
var result = data.map(obj => parseInt(obj.test));
console.log(result);

score 4 · Answer 2 · answered Dec 03 '18 at 15:07

You can use the map method in combination with destructuring to return a new array. + can be used as a coercion operator to change string values into numbers.

data.map(({test}) => +test);

let data = [ { test: '12312311' }, { test: '12312312' }, { test: '12312313' } ],
    
r = data.map(({test}) => +test);

console.log(r);

score 0 · Answer 3 · answered Dec 03 '18 at 15:06

0

It is as easy as a simple forEach. But first you should ignore RowDataPacket somehow, then below code should work.

var numbers = [];
data.forEach(function( item ) {
  numbers.push(parseInt(item.test));
});

answered Dec 03 '18 at 15:06

sadrzadehsina

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Javascript: How to get numbers out of a JavaScript object?

3 Answers3