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1.1.1 • Public • Published


A blazing fast stringifier that safely handles circular objects

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import stringify from "fast-stringify";
const object = {
  foo: "bar",
  deeply: {
    recursive: {
      object: {}
object.deeply.recursive.object = object;
// {"foo":"bar","deeply":{"recursive":{"object":"[ref-0]"}}}


stringify(object: any, replacer: ?function, indent: ?number, circularReplacer: ?function): string

Stringifies the object passed based on the parameters you pass. The only required value is the object. The additional parameters passed will customize how the string is compiled.

  • replacer => function to customize how the value for each key is stringified (see the documentation for JSON.stringify for more details)
  • indent => number of spaces to indent the stringified object for pretty-printing (see the documentation for JSON.stringify for more details)
  • circularReplacer => function to customize how the circular reference is stringified (defaults to [ref-##] where ## is the reference count)


ESM in browsers:

import stringify from "fast-stringify";

ESM in NodeJS:

import stringify from "fast-stringify/mjs";


const stringify = require("fast-stringify").default;


Simple objects

Small number of properties, all values are primitives

Operations / second Relative margin of error
fast-stringify 627,191 0.83%
fast-json-stable-stringify 358,901 0.87%
json-stringify-safe 295,582 0.71%
json-stable-stringify 270,825 0.77%
json-cycle 200,950 0.81%
decircularize 132,202 1.09%

Complex objects

Large number of properties, values are a combination of primitives and complex objects

Operations / second Relative margin of error
fast-stringify 116,915 0.61%
fast-json-stable-stringify 58,603 0.80%
json-cycle 54,115 0.80%
json-stringify-safe 53,851 0.71%
json-stable-stringify 42,827 1.27%
decircularize 23,565 0.86%

Circular objects

Objects that deeply reference themselves

Operations / second Relative margin of error
fast-stringify 106,302 0.74%
json-stringify-safe 50,535 0.64%
json-cycle 50,418 0.89%
decircularize 21,536 0.94%
fast-json-stable-stringify (not supported) 0 0.00%
json-stable-stringify (not supported) 0 0.00%

Special objects

Custom constructors, React components, etc

Operations / second Relative margin of error
fast-stringify 30,971 0.83%
json-cycle 21,324 0.82%
fast-json-stable-stringify 17,909 1.04%
json-stringify-safe 17,522 0.74%
json-stable-stringify 13,938 1.05%
decircularize 7,438 0.64%


Standard practice, clone the repo and npm i to get the dependencies. The following npm scripts are available:

  • benchmark => run benchmark tests against other equality libraries
  • build => build dist files with rollup
  • clean => run clean:dist, clean:es, and clean:lib scripts
  • clean:dist => run rimraf on the dist folder
  • clean:es => run rimraf on the es folder
  • clean:lib => run rimraf on the lib folder
  • dev => start webpack playground App
  • dist => run build and build:minified scripts
  • lint => run ESLint on all files in src folder (also runs on dev script)
  • lint:fix => run lint script, but with auto-fixer
  • prepublish:compile => run lint, test:coverage, transpile:lib, transpile:es, and dist scripts
  • start => run dev
  • test => run AVA with NODE_ENV=test on all files in test folder
  • test:coverage => run same script as test with code coverage calculation via nyc
  • test:watch => run same script as test but keep persistent watcher
  • transpile:es => run Babel on all files in src folder (transpiled to es folder without transpilation of ES2015 export syntax)
  • transpile:lib => run Babel on all files in src folder (transpiled to lib folder)


npm i fast-stringify

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