string_width - v3.1.1

string_width

Package Version Hex 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.

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