string_width

Package VersionHex Docs

gleam add string_width@3

A small package estimating the required number of cells when printing a string on the terminal. It supports all Gleam targets, handles ANSI escape codes, includes useful layout functions, and passes the tests of the NPM string-width package, among others.

It is also one of the fastest options available, even including target-specific ones, while still providing you full flexibility and correctness.

import string_width



pub fn main() {

  string_width.dimensions("hello,\n안녕하세요")

  // --> string_width.Size(rows: 2, columns: 10)



  string_width.line_with(

    "👩‍👩‍👦‍👦",

    string_width.new() |> string_width.mode_2027,

  )

  // --> 2



  // word wrapping and truncation

  string_width.limit(

    "Lorem ipsum dolor sit amet\nIs a common placeholder string",

    to: Size(rows: 3, columns: 10),

    ellipsis: "..."

  )

  // --> "Lorem ipsum dolor\nsit amet\nIs a common place..."



  // position a string inside a box

  string_width.position(

    "XXX",

    in: Size(rows: 3, columns: 10),

    align: Center,

    place: Middle,

    with: "."

  )

  // --> "..........\n...XXX....\n.........."

}

Limitations

Sources

The table lookup technique used by this library is heavily based on the musl libc wcwidth implementation. I built updated tables using the Unicode 16.0 data, and added support for ambiguous characters. It also uses the regex of the ansi-regex npm package, and the test cases of the string-width npm package.