✨ Import text-editor code into the repository

frontend/text-editor/editor/content/Text.js

@@ -0,0 +1,104 @@
+/**
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ *
+ * Copyright (c) KALEIDOS INC
+ */
+
+/**
+ * Throws if the passed value is not a valid offset value.
+ *
+ * @param {*} offset
+ * @throws {TypeError}
+ */
+function tryOffset(offset) {
+  if (!Number.isInteger(offset) || offset < 0)
+    throw new TypeError("Invalid offset");
+}
+
+/**
+ * Throws if the passed value is not a valid string.
+ *
+ * @param {*} str
+ * @throws {TypeError}
+ */
+function tryString(str) {
+  if (typeof str !== "string") throw new TypeError("Invalid string");
+}
+
+/**
+ * Inserts string into a string.
+ *
+ * @param {string} str
+ * @param {number} offset
+ * @param {string} text
+ * @returns {string}
+ */
+export function insertInto(str, offset, text) {
+  tryString(str);
+  tryOffset(offset);
+  tryString(text);
+  return str.slice(0, offset) + text + str.slice(offset);
+}
+
+/**
+ * Replaces a part of a string with a string.
+ *
+ * @param {string} str
+ * @param {number} startOffset
+ * @param {number} endOffset
+ * @param {string} text
+ * @returns {string}
+ */
+export function replaceWith(str, startOffset, endOffset, text) {
+  tryString(str);
+  tryOffset(startOffset);
+  tryOffset(endOffset);
+  tryString(text);
+  return str.slice(0, startOffset) + text + str.slice(endOffset);
+}
+
+/**
+ * Removes text backward from specified offset.
+ *
+ * @param {string} str
+ * @param {number} offset
+ * @returns {string}
+ */
+export function removeBackward(str, offset) {
+  tryString(str);
+  tryOffset(offset);
+  if (offset === 0) {
+    return str;
+  }
+  return str.slice(0, offset - 1) + str.slice(offset);
+}
+
+/**
+ * Removes text forward from specified offset.
+ *
+ * @param {string} str
+ * @param {number} offset
+ * @returns {string}
+ */
+export function removeForward(str, offset) {
+  tryString(str);
+  tryOffset(offset);
+  return str.slice(0, offset) + str.slice(offset + 1);
+}
+
+/**
+ * Removes a slice of text.
+ *
+ * @param {string} str
+ * @param {number} start
+ * @param {number} end
+ * @returns {string}
+ */
+export function removeSlice(str, start, end) {
+  tryString(str);
+  tryOffset(start);
+  tryOffset(end);
+  return str.slice(0, start) + str.slice(end);
+}