@leismore/lmos-nodejs-unicode-print-chars

v1.0.0

Published

5 days ago

A class represents a string of printable characters in Unicode.

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kyle.chinn.admin.leismore

kyle.chinn.leismore

Unicode Printable Characters LMOS for Node.js LMOS Leismore OpenSource Leismore Node.js NodeJS Node

lmos-nodejs-unicode-print-chars

A class represents a string of printable characters in Unicode.

A robust Node.js utility to validate, sanitize, and ensure strings contain only safe, printable Unicode characters.

Motivation

In text processing, certain characters are invisible but active. Legacy control characters like BEL (ASCII 07) can trigger machine bells, while DEL (ASCII 7F) can alter text streams.

If an online form accepts user input and blindly processes it without validation, malicious or malformed inputs containing hidden control characters can disrupt your application, break JSON parsing, corrupt logs, or exploit text-rendering engines.

While modern frameworks offer basic protections, the safest practice is defense-in-depth: stopping unwanted characters at the very beginning of their journey.

This package provides a strict boundary for user data, ensuring that your strings consist entirely of valid, safe, and visible printable characters across the Unicode spectrum.

Installation

npm install @leismore/lmos-nodejs-unicode-print-chars

Test

npm test

Build

npm run build

Examples


import { PrintableCharsUni, PCUError } from '@leismore/lmos-nodejs-unicode-print-chars';

const STRING_VALID_EN = 'I know that I know nothing. 🏛️';
const STRING_VALID_ZH = '我唯一知道的就是我一无所知。';
const STRING_VALID_JP = '私は自分が何も知らないということだけを知っている。';

// Throws PCUError, if illegal characters
const pcuEN = new PrintableCharsUni(STRING_VALID_EN);
const pcuZH = new PrintableCharsUni(STRING_VALID_ZH);
const pcuJP = new PrintableCharsUni(STRING_VALID_JP);

/**
 * Output:
 * - I know that I know nothing. 🏛️
 * - 我唯一知道的就是我一无所知。
 * - 私は自分が何も知らないということだけを知っている。
 */

console.log(String(pcuEN));
console.log(String(pcuZH));
console.log(String(pcuJP));

API Reference

Exports

export { PCUError, PrintableCharsUni };
export type { PCUErrorErr };

PCUError

PCUError Class Properties

error : PCUErrorErr
previous? : Error
timestamp : Date

PCUError is the Error class for this package. All errors thrown by this library are instances of this class, allowing you to easily catch and handle them in your application.

PCUError extends the LMError class from @leismore/lmos-nodejs-lmerror. For more details, please refer to the documentation of @leismore/lmos-nodejs-lmerror.

PCUErrorErr

type PCUErrorErr = {
  readonly message: string, // Message for human. Only ASCII printable characters allowed.
  readonly code:    string  // Code for machine. Only letter, number, and underscore allowed.
};

PrintableCharsUni

class PrintableCharsUni {

    /**
     * @throws {PCUError}
     * 2    invalid_string
     */
    constructor(chars: string)

    public toString(): string

    public static isValid(chars: string): boolean

    /**
     * @throws {PCUError}
     * 3    not_string
     */
    public static removeInvalidChars(chars: string): string

}

PrintableCharsUni class represents a string of printable characters in Unicode.