Parse large JSON

Parse JSON in chunks so that weak devices can still function. e.g. allow mobile phones to load decently sized JSON objects without blocking user interaction.

Install

npm

npm i parse-large-json --save

yarn

yarn add parse-large-json

Usage

const parse = require('parse-large-json')

const hugeJSONstring = '{"big":true}' // no whitespaces allowed!
const maxChunkSize = 100e3 

parse(hugeJSONstring, maxChunkSize).then(({val, rest}) => {
  if (rest) {
    throw Error('wicked string?')
  }
  console.log('parsed it!', val)
})

Workings

parse-large-json works by looking ahead in the string up to maxChunkSize, and determining if the first thing it sees there is an Object it can parse synchronously using JSON.parse. If this is not the case, it starts reading the string, parsing "primitives" synchronously, but passing any Object handling to the next tick using a Promise.

This way, the user can control the balance between

• large amount of small chunks (less blockage, more promises, more time)
• small amount of large chunks (more blocakge, less promises, less time)