Truncate a string to the given length in bytes. Correctly handles multi-byte characters and surrogate pairs.

A browser implementation that doesn't use Buffer.byteLength is provided to minimize build size.

var truncate = require("truncate-utf8-bytes")
var str = "a☃" // a = 1 byte, ☃ = 3 bytes
console.log(truncate(str, 2))
// -> "a"

When using browserify or webpack, this automatically resolves to an implementation that does not use Buffer.byteLength.

Returns string truncated to at most length bytes in length.