无法在Node.js中解析JSON

Question

I am trying to parse JSON that looks like this:

{ "values" : [{ "alpha":8 },{ "beta":4 },{ "gamma":-3 } ]}

I'm parsing it with: console.log(msg.values.alpha) , and get:

Missing error handler on `socket`.
TypeError: Cannot read property 'alpha' of undefined

This is how I have seen done it on other sites. Doing it with console.log(msg.values) returns undefined , and just running console.log(msg) returns proper JSON . I have seen other people with this issue, but nothing that is said to do is working. Thanks!

Answer 1

Don't forget to parse it to an object using JSON.parse

msg.values is an array. Technically you would have to access it via msg.values[0].alpha.

Better solution.

if you are using underscore npm install underscore

var _ = require('underscore');
var msg = JSON.parse('{ "values" : [{ "alpha":8 },{ "beta":4 },{ "gamma":-3 } ]}');
var alpha = _.find(msg.values, function (value) {
    return value.hasOwnProperty('alpha');
}).alpha;

The underscore solution would allow you to not rely on the order of the array so its probably better style.

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Here is a fiddle of my code running in a browser.