Truncate-json NPM

Truncate a JSON string.

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Examples

import truncateJson from 'truncate-json'

// Object properties and array items beyond `maxSize` are omitted.
const maxSize = 15
const jsonString = JSON.stringify({ a: 'one', b: 'two' })
console.log(jsonString)
// '{"a":"one","b":"two"}' (21 bytes)
console.log(truncateJson(jsonString, maxSize).jsonString)
// '{"a":"one"}' (11 bytes)

// Works deeply inside objects and arrays
const jsonString = JSON.stringify([
  'one',
  { a: 'two', b: { c: 'three', d: 'four' } },
  'five',
])
console.log(jsonString)
// '["one",{"a":"two","b":{"c":"three","d":"four"}},"five"]' (55 bytes)
const returnValue = truncateJson(jsonString, 40)
console.log(returnValue.jsonString)
// '["one",{"a":"two","b":{"c":"three"}}]' (37 bytes)

// Omitted/truncated properties are returned
console.log(returnValue.truncatedProps)
// [
//   { path: [ 1, 'b', 'd' ], value: 'four' },
//   { path: [ 2 ], value: 'five' }
// ]
const isTruncated = returnValue.truncatedProps.length !== 0
console.log(isTruncated) // true

// Indentation is automatically detected and preserved
const jsonString = JSON.stringify({ a: 'one', b: 'two' }, undefined, 2)
console.log(jsonString)
// '{
//   "a": "one",
//   "b": "two"
// }' (30 bytes)
console.log(truncateJson(jsonString, 25).jsonString)
// '{
//   "a": "one"
// }' (16 bytes)

// The top-level value can be any JSON type, not only objects or arrays
const jsonString = JSON.stringify('This is an example top-level string')
console.log(truncateJson(jsonString, 25).jsonString)
// '"This is an example t..."' (25 bytes)

Install

npm install truncate-json

This package works in both Node.js >=18.18.0 and browsers.

This is an ES module. It must be loaded using an import or import() statement, not require(). If TypeScript is used, it must be configured to output ES modules, not CommonJS.