117 lines
3.6 KiB
JavaScript
117 lines
3.6 KiB
JavaScript
const usernameField = document.getElementById("field-username");
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const usernameOutput = document.getElementById("field-username-output");
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const form = document.getElementById("form");
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// needed to validate on change event when no input was changed
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let needsValidation = true;
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let isValid = false;
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function throttle(fn, wait) {
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let timeout;
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const throttleFn = function() {
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const args = Array.from(arguments);
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if (timeout) {
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clearTimeout(timeout);
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}
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timeout = setTimeout(fn.bind.apply(fn, [null].concat(args)), wait);
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};
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throttleFn.cancelQueued = function() {
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clearTimeout(timeout);
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};
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return throttleFn;
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}
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function checkUsernameAvailable(username) {
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let check_uri = 'check?username=' + encodeURIComponent(username);
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return fetch(check_uri, {
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// include the cookie
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"credentials": "same-origin",
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}).then(function(response) {
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if(!response.ok) {
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// for non-200 responses, raise the body of the response as an exception
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return response.text().then((text) => { throw new Error(text); });
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} else {
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return response.json();
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}
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}).then(function(json) {
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if(json.error) {
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return {message: json.error};
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} else if(json.available) {
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return {available: true};
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} else {
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return {message: username + " is not available, please choose another."};
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}
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});
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}
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const allowedUsernameCharacters = new RegExp("^[a-z0-9\\.\\_\\-\\/\\=]+$");
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const allowedCharactersString = "lowercase letters, digits, ., _, -, /, =";
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function reportError(error) {
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throttledCheckUsernameAvailable.cancelQueued();
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usernameOutput.innerText = error;
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usernameOutput.classList.add("error");
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usernameField.parentElement.classList.add("invalid");
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usernameField.focus();
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}
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function validateUsername(username) {
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isValid = false;
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needsValidation = false;
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usernameOutput.innerText = "";
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usernameField.parentElement.classList.remove("invalid");
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usernameOutput.classList.remove("error");
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if (!username) {
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return reportError("Please provide a username");
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}
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if (username.length > 255) {
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return reportError("Too long, please choose something shorter");
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}
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if (!allowedUsernameCharacters.test(username)) {
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return reportError("Invalid username, please only use " + allowedCharactersString);
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}
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usernameOutput.innerText = "Checking if username is available …";
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throttledCheckUsernameAvailable(username);
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}
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const throttledCheckUsernameAvailable = throttle(function(username) {
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const handleError = function(err) {
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// don't prevent form submission on error
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usernameOutput.innerText = "";
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isValid = true;
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};
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try {
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checkUsernameAvailable(username).then(function(result) {
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if (!result.available) {
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reportError(result.message);
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} else {
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isValid = true;
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usernameOutput.innerText = "";
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}
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}, handleError);
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} catch (err) {
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handleError(err);
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}
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}, 500);
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form.addEventListener("submit", function(evt) {
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if (needsValidation) {
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validateUsername(usernameField.value);
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evt.preventDefault();
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return;
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}
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if (!isValid) {
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evt.preventDefault();
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usernameField.focus();
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return;
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}
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});
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usernameField.addEventListener("input", function(evt) {
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validateUsername(usernameField.value);
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});
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usernameField.addEventListener("change", function(evt) {
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if (needsValidation) {
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validateUsername(usernameField.value);
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}
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});
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