Decancer: A Rust Library for Removing Unicode Confusables


A tiny package that removes common unicode confusables/homoglyphs from strings.

  • Its core is written in Rust and utilizes a form of Binary Search to ensure speed!
  • It's capable of filtering 215,361 (19.33%) different unicode codepoints like:
  • Unlike other packages, this package is unicode bidi-aware in a way that it also interprets right-to-left characters in the same way as it were to be rendered by an application.
  • And it's available in the following languages:


Rust (v1.64 or later)

In your Cargo.toml:

decancer = "2.0.1"

JavaScript (Node.js)

In your shell:

$ npm install decancer

In your code (CommonJS):

const decancer = require('decancer')

In your code (ESM):

import decancer from 'decancer'

JavaScript (Browser)

In your code:

<script type="module">
  import init from ''

  const decancer = await init()



Building from source


$ git clone --depth 1
$ cd decancer/bindings/native
$ cargo build --release

And the binary files should be generated in the target/release directory.



For more information, please read the documentation.

let cured = decancer::cure("vοΌ₯ⓑ𝔂 π”½π•ŒΕ‡β„•ο½™ ţ乇𝕏𝓣").unwrap();

assert_eq!(cured, "very funny text");
assert_eq!(cured.into_str(), String::from("very funny text"));

JavaScript (Node.js)

const assert = require('node:assert')
const cured = decancer('vοΌ₯ⓑ𝔂 π”½π•ŒΕ‡β„•ο½™ ţ乇𝕏𝓣')

assert(cured.equals('very funny text'))

// => 'very funny text'

JavaScript (Browser)

<!DOCTYPE html>
<html lang="en">
    <meta charset="utf-8" />
    <title>Decancerer!!! (tm)</title>
      textarea {
        font-size: 30px;

      #cure {
        font-size: 20px;
        padding: 5px 30px;
    <h3>Input cancerous text here:</h3>
    <textarea rows="10" cols="30"></textarea>
    <br />
    <button id="cure" onclick="cure()">cure!</button>
    <script type="module">
      import init from ''

      const decancer = await init()

      window.cure = function () {
        const textarea = document.querySelector('textarea')

        if (!textarea.value.length) {
          return alert("There's no text!!!")

        textarea.value = decancer(textarea.value).toString()

See this in action here.


#include <decancer.h>

#include <string.h>
#include <stdlib.h>
#include <stdio.h>

// global variable for assertion purposes only
decancer_cured_t cured;

static void assert(const bool expr, const char *message)
    if (!expr)
        fprintf(stderr, "assertion failed (%s)\n", message);

static void print_error(decancer_error_t error_code)
    char message[90];
    uint8_t message_size;
    const uint8_t *ptr = decancer_error(error_code, &message_size);
    memcpy(message, ptr, message_size);
    // rust strings are NOT null-terminated
    message[message_size] = '\0';
    fprintf(stderr, "error: %s", message);

int main(void) {
    decancer_error_t error_code;

    // utf-8 bytes for "vοΌ₯ⓑ𝔂 π”½π•ŒΕ‡β„•ο½™ ţ乇𝕏𝓣"
    uint8_t string[] = {0x76, 0xef, 0xbc, 0xa5, 0xe2, 0x93, 0xa1, 0xf0, 0x9d, 0x94, 0x82, 0x20, 0xf0, 0x9d,
                        0x94, 0xbd, 0xf0, 0x9d, 0x95, 0x8c, 0xc5, 0x87, 0xe2, 0x84, 0x95, 0xef, 0xbd, 0x99,
                        0x20, 0xc5, 0xa3, 0xe4, 0xb9, 0x87, 0xf0, 0x9d, 0x95, 0x8f, 0xf0, 0x9d, 0x93, 0xa3};

    cured = decancer_cure(string, sizeof(string), &error_code);

    if (cured == NULL)
        return 1;

    assert(decancer_equals(cured, (uint8_t *)("very funny text"), 15), "equals");
    assert(decancer_contains(cured, (uint8_t *)("funny"), 5), "contains");

    // coerce output as a raw UTF-8 pointer and retrieve its size (in bytes)
    size_t output_size;
    const uint8_t *output_raw = decancer_raw(cured, &output_size);

    assert(output_size == 15, "raw output size");

    // utf-8 bytes for "very funny text"
    const uint8_t expected_raw[] = {0x76, 0x65, 0x72, 0x79, 0x20, 0x66, 0x75, 0x6e,
                                    0x6e, 0x79, 0x20, 0x74, 0x65, 0x78, 0x74};

    char assert_message[38];
    for (uint32_t i = 0; i < sizeof(expected_raw); i++)
        sprintf(assert_message, "mismatched utf-8 contents at index %u", i);
        assert(output_raw[i] == expected_raw[i], assert_message);

    return 0;


Please read for newbie contributors who want to contribute!

Download details:

Author: null8626

License: MIT license


Decancer: A Rust Library for Removing Unicode Confusables
1.10 GEEK