reduce size

public/challenge.json

@@ -1,5 +1,5 @@
 {
   "algo": "SHA-256",
-  "prefixBits": "15",
+  "prefixBits": 15,
   "input": "challenge:"
 }

src/challenge.ts

@@ -5,6 +5,5 @@ export type Challenge = {
     input: string,
 }
 
-export function validateChallenge(challenge: Challenge): boolean {
-    return !!challenge.algo && challenge.prefixBits > 0 && !!challenge.input;
-}
+export const validateChallenge = (challenge: Challenge): boolean =>
+    !!challenge.algo && challenge.prefixBits > 0 && !!challenge.input;

src/content.ts

@@ -1,18 +0,0 @@
-const suffixCharset = [
-    "0123456789",
-    "abcdefghijklmnopqrstuvwxyz",
-    "ABCDEFGHIJKLMNOPQRSTUVWXYZ",
-    "+-",
-].flatMap(set => set.split(""));
-const suffixCharsetBits = 6;
-
-export function makeSuffix(index: number): string {
-    let result = "";
-
-    while (index > 0) {
-        result += suffixCharset[index & ((1 << suffixCharsetBits) - 1)];
-        index >>= suffixCharsetBits;
-    }
-
-    return result;
-}

src/default-styles.css

@@ -2,7 +2,7 @@
     width: 300px;
     height: 70px;
     padding: 19px;
-    border: 1px solid grey;
+    border: 1px solid #888;
     box-sizing: border-box;
     font-size: 20px;
     font-family: sans-serif;
@@ -19,18 +19,18 @@
     height: 30px;
     width: 30px;
     display: inline-block;
-    background-color: white;
+    background-color: #fff;
     cursor: pointer;
-    border: 1px solid black;
+    border: 1px solid #000;
     border-radius: 3px;
 }
 
 .captcha .checkbox:hover {
-    background-color: lightgrey;
+    background-color: #eee;
 }
 
 .captcha .checkbox.checked {
-    background-color: #2196F3;
+    background-color: #29F;
 }
 
 .captcha .checkbox.checked::before {
@@ -41,7 +41,7 @@
     height: 15px;
     top: 2px;
     left: 9px;
-    border: white solid;
+    border: #fff solid;
     border-width: 0 5px 5px 0;
     transform: rotate(45deg);
 }
@@ -59,11 +59,11 @@
     height: 17px;
     border: 4px solid;
     border-radius: 50%;
-    border-color: black transparent black transparent;
-    animation: captchaLoading infinite 1s;
+    border-color: #000 transparent #000 transparent;
+    animation: _aw_l infinite 1s;
 }
 
-@keyframes captchaLoading {
+@keyframes _aw_l {
     to {
         transform: rotate(.5turn)
     }

src/hash.ts

@@ -1,6 +1,3 @@
-const hexCharset = "0123456789abcdef".split("");
-
-export const sha256: AlgorithmIdentifier = "SHA-256";
 
 declare global {
     interface Uint8Array {
@@ -10,7 +7,7 @@ declare global {
 }
 
 Uint8Array.prototype.toHex = function(): string {
-    return [...this].map(c => hexCharset[c >> 4] + hexCharset[c & 15]).join("");
+    return [...this].map(c => (c >> 4).toString(16) + (c & 15).toString(16)).join("");
 };
 
 Uint8Array.prototype.hasPrefix = function(prefix: Uint8Array, bits: number): boolean {
@@ -27,6 +24,5 @@ Uint8Array.prototype.hasPrefix = function(prefix: Uint8Array, bits: number): boo
     return true;
 };
 
-export async function digest(algo: AlgorithmIdentifier, input: string): Promise<Uint8Array> {
-    return new Uint8Array(await crypto.subtle.digest(algo, new TextEncoder().encode(input)));
-}
+export const digest = async (algo: AlgorithmIdentifier, input: string): Promise<Uint8Array> =>
+    new Uint8Array(await crypto.subtle.digest(algo, new TextEncoder().encode(input)));

src/main.ts

@@ -1,16 +1,19 @@
-import {makeSuffix} from "./content";
-import {digest, sha256} from "./hash";
+import {digest} from "./hash";
 
 import "./default-styles.css";
 import {Challenge, validateChallenge} from "./challenge";
 
-async function findHashWithPrefix(hashPrefixBits: number, inputPrefix: string): Promise<string> {
+const CLASS_CHECKBOX = "checkbox";
+const CLASS_LOADING = "loading";
+const CLASS_CHECKED = "checked";
+
+const findHashWithPrefix = async (algo: string, hashPrefixBits: number, inputPrefix: string): Promise<string> => {
     const hashPrefix = new Uint8Array(Array(Math.ceil(hashPrefixBits / 8)).map(_ => 0));
     let iteration = 0;
     
     do {
-        var message = inputPrefix + makeSuffix(iteration++);
-        var hash = await digest(sha256, message);
+        var message = inputPrefix + (iteration++).toString(36);
+        var hash = await digest(algo, message);
     } while (!hash.hasPrefix(hashPrefix, hashPrefixBits));
     
     return message;
@@ -18,54 +21,56 @@ async function findHashWithPrefix(hashPrefixBits: number, inputPrefix: string):
 
 function initCaptchaContentAndGetCheckbox(captcha: Element): Element {
     const checkbox = document.createElement("div");
-    checkbox.classList.add("checkbox");
-    captcha.append(checkbox);
+    checkbox.classList.add(CLASS_CHECKBOX, CLASS_LOADING);
 
     const text = document.createElement("span");
     text.innerText = "I am not a robot";
-    captcha.append(text);
+
+    captcha.append(checkbox, text);
 
     return checkbox;
 }
 
+const toggleChecked = (checkbox: Element) =>
+    checkbox.classList.toggle(CLASS_CHECKED);
+
+const toggleLoading = (checkbox: Element) =>
+    checkbox.classList.toggle(CLASS_LOADING);
+
 function prepareChallengeExecution(challenge: Challenge): () => Promise<void> {
     return async function() {
         console.log("Calculating...");
 
-        this.classList.add("loading");
+        toggleLoading(this);
 
-        const response = await findHashWithPrefix(challenge.prefixBits, challenge.input);
+        const response = await findHashWithPrefix(challenge.algo, challenge.prefixBits, challenge.input);
         console.log("Challenge Response: " + response);
 
-        this.classList.remove("loading");
-        this.classList.add("checked");
+        toggleLoading(this);
+        toggleChecked(this);
     }
 }
 
-async function prepareCaptcha(captcha: Element) {
+const prepareCaptcha = async (captcha: Element) => {
     const challengeUrl = captcha.getAttribute("data-challenge-url");
     if (!challengeUrl) {
-        console.warn("No challenge URL found.");
-        return;
+        throw "No challenge URL found.";
     }
 
     const checkbox = initCaptchaContentAndGetCheckbox(captcha);
-    checkbox.classList.add("loading");
 
     const challengeResponse = await fetch(challengeUrl);
     const challenge = await challengeResponse.json() as Challenge;
 
     if (!validateChallenge(challenge)) {
-        console.warn("Challenge is invalid.");
-        return;
+        throw "Challenge is invalid.";
     }
 
-    checkbox.classList.remove("loading");
+    toggleLoading(checkbox);
 
     checkbox.addEventListener("click", prepareChallengeExecution(challenge));
 }
 
-window.addEventListener("load", () => {
-    console.log("load");
-    [...document.getElementsByClassName("captcha")].forEach(prepareCaptcha);
-});
+window.addEventListener("load", () =>
+    [...document.getElementsByClassName("captcha")].forEach(prepareCaptcha)
+);