How can I print a circular structure in a JSON-like format?

javascript json node.js
Harry picture Harry · Jul 23, 2012 · Viewed 766.2k times · Source

I have a big object I want to convert to JSON and send. However it has circular structure. I want to toss whatever circular references exist and send whatever can be stringified. How do I do that?

Thanks.

var obj = {
  a: "foo",
  b: obj
}

I want to stringify obj into:

{"a":"foo"}

Answer

Erel Segal-Halevi picture Erel Segal-Halevi · Aug 21, 2013

In Node.js, you can use util.inspect(object). It automatically replaces circular links with "[Circular]".

Albeit being built-in (no installation is required), you must import it

import * as util from 'util' // has no default export
import { inspect } from 'util' // or directly
// or 
var util = require('util')
To use it, simply call 
console.log(util.inspect(myObject))

Also be aware that you can pass options object to inspect (see link above)

inspect(myObject[, options: {showHidden, depth, colors, showProxy, ...moreOptions}])

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