watson / unicode-byte-truncate

Unicode aware Node.js module that truncates a string to a given max byte size

unicode-byte-truncate

Truncate a string to a given byte size by removing bytes from the right while making sure not to slice in the middle of a multi-byte unicode character.

Installation

npm install unicode-byte-truncate --save

Usage

var trunc = require('unicode-byte-truncate')

var str = 'foo🎉bar' // 10 byte string - byte 4 to 7 is a single character

console.log(trunc(str, 4)) // `foo` == 0x666F6F (3 bytes)
console.log(trunc(str, 5)) // `foo` == 0x666F6F (3 bytes)
console.log(trunc(str, 6)) // `foo` == 0x666F6F (3 bytes)
console.log(trunc(str, 7)) // `foo🎉` == 0x666F6FF09F8E89 (7 bytes)

API

The unicode-byte-truncate module exposes a single trunc function.

result = trunc(string, maxBytes)

Given a string and a maxBytes integer greater than or equal to zero, the trunc function will slice characters off the end of the string to ensure that it doesn't contain more bytes than specified by the maxBytes argument.

The truncated string will be returned as the result.

The trunc function is multi-byte unicode aware and will never cut up surrogate pairs. This means that the result may contain fewer bytes than specified by the maxBytes argument.

License

MIT