jitson

library1.0.0jsnpmunverified

Just-In-Time JSON.parse compiler that optimizes parsing by schema sampling. Version 1.0.0 is stable. It samples incoming JSON data and if a stable schema is detected, compiles a fast parser using turbo-json-parse. Differentiators: JIT compilation based on runtime schema analysis, supports Node.js buffers for faster parsing. Maintained by mafintosh. Release cadence is low; no recent updates.

serialization data

npm install jitson

github ↗package ↗

INSTALL

IMPORT

SIG · JITSON

jitson

serializationjavascriptv1.0.0

harness data pending

Install & Compatibility

Where this runs

No compatibility data collected yet for this library.

Code

Verified usage

Verified import paths — ran on the pinned version, not inferred.

default (jitson function)

✓ import jitson from 'jitson'

✗ const jitson = require('jitson')

Package is ESM-only; use ESM import or dynamic import() in CommonJS.

jitson constructor

✓ const parse = jitson()

✗ const parse = new jitson()

jitson is a factory function, not a class. Do not use 'new'.

parse function

✓ const obj = parse(jsonString)

✗ parse(JSON.parse(jsonString))

parse expects a JSON string or Buffer, not a parsed object.

parse.schema

✓ const schema = parse.schema

After parsing, check parse.schema to see if an optimized parser is being used (null if not).

Demonstrates JIT compilation: after several parses with a stable schema, parse.schema becomes non-null.

import jitson from 'jitson'; const parse = jitson({ sampleInterval: 10 }); for (let i = 0; i < 10; i++) { const obj = parse(JSON.stringify({ hello: 'world', number: Math.random() })); console.log(obj); } console.log('Optimized schema:', parse.schema);

Debug

Known issues

gotchajitson is not a class; do not use 'new'.

fix

Call jitson() directly (const parse = jitson()).

affects: >=1.0.0

gotchaThe parse function expects a string or Buffer, not a parsed object.

fix

Pass JSON.stringify output to parse, not JSON.parse output.

affects: >=1.0.0

gotchaThe underlying turbo-json-parse may fail for very complex or nested schemas.

fix

Fall back to JSON.parse manually if jitson throws.

affects: >=1.0.0

gotchaSchema detection works best when each endpoint uses a separate jitson instance.

fix

Create one jitson instance per API endpoint or data source.

affects: >=1.0.0

Errors

Common errors & fixes

TypeError: jitson is not a constructor

Using 'new jitson()' instead of calling jitson() as a function.

fix

const parse = jitson(); // No 'new' keyword

TypeError: parse.schema is not an object

Accessing parse.schema before any parsing has been done.

fix

Call parse() at least once before checking parse.schema. After schema stabilization it will be an object.

Error: Unable to compile parser - schema too complex

The JSON schema is too complex for turbo-json-parse to compile.

fix

Simplify the JSON data structure or fall back to JSON.parse.

Upgrade

Version history

1.0.0latest on npm

Audit

Dependencies

turbo-json-parserequiredUses turbo-json-parse to compile optimized parsers when schema is stable.

Agent activity

6 hits · last 30 days

node

Resources

githubhttps://github.com/mafintosh/jitson ↗

packagehttps://www.npmjs.com/package/jitson ↗