[Frontend] Settings for profile fields (#1885)

* get max emoji size from instance settings

* expose (hardcoded) max amount of profile fields in instance api

* basic profile field setting

* fix profile field hook structure for updates

* *twirls mustache* fix ze tests

---------

Co-authored-by: tsmethurst <tobi.smethurst@protonmail.com>

web/source/settings/lib/form/field-array.jsx

@@ -0,0 +1,65 @@
+/*
+	GoToSocial
+	Copyright (C) GoToSocial Authors admin@gotosocial.org
+	SPDX-License-Identifier: AGPL-3.0-or-later
+
+	This program is free software: you can redistribute it and/or modify
+	it under the terms of the GNU Affero General Public License as published by
+	the Free Software Foundation, either version 3 of the License, or
+	(at your option) any later version.
+
+	This program is distributed in the hope that it will be useful,
+	but WITHOUT ANY WARRANTY; without even the implied warranty of
+	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+	GNU Affero General Public License for more details.
+
+	You should have received a copy of the GNU Affero General Public License
+	along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+"use strict";
+
+const React = require("react");
+
+const getFormMutations = require("./get-form-mutations");
+
+function parseFields(entries, length) {
+	const fields = [];
+
+	for (let i = 0; i < length; i++) {
+		if (entries[i] != undefined) {
+			fields[i] = Object.assign({}, entries[i]);
+		} else {
+			fields[i] = {};
+		}
+	}
+
+	return fields;
+}
+
+module.exports = function useArrayInput({ name, _Name }, { initialValue, length = 0 }) {
+	const fields = React.useRef({});
+
+	const value = React.useMemo(() => parseFields(initialValue, length), [initialValue, length]);
+
+	return {
+		name,
+		value,
+		ctx: fields.current,
+		maxLength: length,
+		selectedValues() {
+			// if any form field changed, we need to re-send everything
+			const hasUpdate = Object.values(fields.current).some((fieldSet) => {
+				const { updatedFields } = getFormMutations(fieldSet, { changedOnly: true });
+				return updatedFields.length > 0;
+			});
+			if (hasUpdate) {
+				return Object.values(fields.current).map((fieldSet) => {
+					return getFormMutations(fieldSet, { changedOnly: false }).mutationData;
+				});
+			} else {
+				return [];
+			}
+		}
+	};
+};