How to parse json in js?

Question

I need to parse a json object like {"key1":"val1","key2":"val2","key3":"val3"} in a loop.

Trying:

var inobj = '[{"key1":"val1","key2":"val2","key3":"val3"}]';
var obj = eval(inobj);
    for (var i = 0; i < 3; i++) {
        var key = i;
        var val = obj[key];
        alert (key+' = '+val);
    }

But i don't know hot to know obj.length.

Related: stackoverflow.com/questions/4935632/… and stackoverflow.com/questions/11922383/… — Felix Kling
– Felix Kling, Commented Nov 6, 2012 at 6:59

Domenic · Accepted Answer · 2012-11-06 06:56:53Z

5

var obj = JSON.parse('{"key1":"val1","key2":"val2","key3":"val3"}');

Object.keys(obj).forEach(function (key) {
    alert(key + " = " + obj[key]);
});

answered Nov 6, 2012 at 6:56

Domenic

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4 Comments

Felix Kling Over a year ago

Or simply for (var key in obj) {...}.

Domenic Over a year ago

@FelixKling I prefer the Object.keys(obj).forEach(function (key) { .. }) approach since it creates a new scope, avoiding the hoisting issues inherent in for loops.

Felix Kling Over a year ago

If a new scope is required then yes, it's a nice approach... otherwise, a simple for seems to have less overhead.

Domenic Over a year ago

Yeah, I mean, in this example a new scope is not necessarily required, but I can just imagine this user's next question being "why when I call setTimeout inside my for loop does it not work like I expect..." :)

Community · Accepted Answer · 2017-05-23 12:18:41Z

1

You can count poperties:

Object.keys(obj).length

see stack question: How to efficiently count the number of keys/properties of an object in JavaScript?

edited May 23, 2017 at 12:18

CommunityBot

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answered Nov 6, 2012 at 6:57

karaxuna

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