mysticatea / eaw

The Node.js module to calculate the width of east Asian characters.

eaw

The Node.js module to calculate the width of east Asian characters. (based on Unicode 9.0.0)

The script of this module is generated with EastAsianWidth.txt that Unicode Character Database provides.

• The generator script is ./scripts/generate.js.
• The generated script is ./lib/is-narrow-character.js.

The generator script is used to maintain this module as following to latest Unicode.

💿 Installation

This module can be installed by npm.

$ npm install --save eaw

• It requires Node.js >=4.0.0.
• It can be used in browsers by browserify-like tools.

📖 Usage

CLI

This module provides a CLI command: eaw

The command calculates the width of east Asian characters for each line.

Usage: eaw [OPTIONS]

    It calculates the width of given east Asian characters.
    It reads the characters from stdin or `--text` option.

    OPTIONS:
        -s, --split <NUMBER> ... It splits the given text by LF to make the
                                 width of each line shorter than the given
                                 number.
        -t, --text <TEXT> ...... The characters that eaw processes instead of
                                 stdin.

Example:
    $ eaw --text "hello, 世界"
    11
    $ cat hello.txt | eaw
    11
    $ cat hello.txt | eaw --split 4
    hell
    o,
    世界

Node.js

This module provides Node.js module.

const eaw = require("eaw")

console.log(eaw.isNarrowCharacter("A"))              // → true
console.log(eaw.isNarrowCharacter("あ"))             // → false
console.log(eaw.getWidth("A"))                       // → 1
console.log(eaw.getWidth("あ"))                      // → 2
console.log(eaw.getWidth("hello, 世界"))             // → 11
console.log(eaw.getWidth(["hello, 世界", "🌟❤"]))   // → [11, 4]
console.log(eaw.split("hello, 世界", 4))             // → ["hell", "o, ", "世界"]
console.log(eaw.split(["hello, 世界", "🌟❤👍"], 4)) // → ["hell", "o, ", "世界", "🌟❤", "👍"]

process.stdin
    .pipe(eaw.createWidthStream())
    .pipe(process.stdout)

process.stdin
    .pipe(eaw.createSplitStream(4))
    .pipe(process.stdout)

eaw.isNarrowCharacter(character: string): boolean

It checks whether the given character is a narrow character or not.

This function checks the first code point if the argument has 2 or more characters.

eaw.getWidth(characters: string, widthOfWideCharacters?: number = 2): number
eaw.getWidth(characters: string[], widthOfWideCharacters?: number = 2): number[]
eaw.getWidth(characters: Iterable<string>, widthOfWideCharacters?: number = 2): Iterable<number>

It returns the total width of the given characters.

eaw.split(characters: string, maxPerLine: number, widthOfWideCharacters?: number = 2): string[]
eaw.split(characters: string[], maxPerLine: number, widthOfWideCharacters?: number = 2): string[]
eaw.split(characters: Iterable<string>, maxPerLine: number, widthOfWideCharacters?: number = 2): Iterable<string>

It splits the given characters to make the width of each line shorter than the given number.

eaw.createWidthStream(widthOfWideCharacters?: number = 2): stream.Transform

It returns the transform stream to calculate the width of each line.

eaw.createSplitStream(maxPerLine: number, widthOfWideCharacters?: number = 2): stream.Transform

It returns the transform stream to split the given characters to make the width of each line shorter than the given number.

📰 Changelog

See GitHub Releases

💪 Contributing

Welcom your contributing!

Please use GitHub's issues/PRs.

Development tools

• npm test runs tests.
• npm run build generates the script from EastAsianWidth.txt.
• npm run clean removes the coverage result of the last npm test command.
• npm run coverage opens the coverage of the last npm test command by browsers.
• npm run lint runs ESLint.
• npm run watch runs tests for each file change.