onedeuxtriseigo.nullpo.dev
Pop-up dictionary browser extension for language learning. Successor to Yomichan. (PERSONAL FORK)
1/*
2 * Copyright (C) 2023-2025 Yomitan Authors
3 * Copyright (C) 2022 Yomichan Authors
4 *
5 * This program is free software: you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License as published by
7 * the Free Software Foundation, either version 3 of the License, or
8 * (at your option) any later version.
9 *
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 * GNU General Public License for more details.
14 *
15 * You should have received a copy of the GNU General Public License
16 * along with this program. If not, see <https://www.gnu.org/licenses/>.
17 */
18
19/**
20 * Reads code points from a string in the forward direction.
21 * @param {string} text The text to read the code points from.
22 * @param {number} position The index of the first character to read.
23 * @param {number} count The number of code points to read.
24 * @returns {string} The code points from the string.
25 */
26export function readCodePointsForward(text, position, count) {
27 const textLength = text.length;
28 let result = '';
29 for (; count > 0; --count) {
30 const char = text[position];
31 result += char;
32 if (++position >= textLength) { break; }
33 const charCode = char.charCodeAt(0);
34 if (charCode >= 0xd800 && charCode < 0xdc00) { // charCode is a high surrogate code
35 const char2 = text[position];
36 const charCode2 = char2.charCodeAt(0);
37 if (charCode2 >= 0xdc00 && charCode2 < 0xe000) { // charCode2 is a low surrogate code
38 result += char2;
39 if (++position >= textLength) { break; }
40 }
41 }
42 }
43 return result;
44}
45
46/**
47 * Reads code points from a string in the backward direction.
48 * @param {string} text The text to read the code points from.
49 * @param {number} position The index of the first character to read.
50 * @param {number} count The number of code points to read.
51 * @returns {string} The code points from the string.
52 */
53export function readCodePointsBackward(text, position, count) {
54 let result = '';
55 for (; count > 0; --count) {
56 const char = text[position];
57 result = char + result;
58 if (--position < 0) { break; }
59 const charCode = char.charCodeAt(0);
60 if (charCode >= 0xdc00 && charCode < 0xe000) { // charCode is a low surrogate code
61 const char2 = text[position];
62 const charCode2 = char2.charCodeAt(0);
63 if (charCode2 >= 0xd800 && charCode2 < 0xdc00) { // charCode2 is a high surrogate code
64 result = char2 + result;
65 if (--position < 0) { break; }
66 }
67 }
68 }
69 return result;
70}
71
72/**
73 * Trims and condenses trailing whitespace and adds a space on the end if it needed trimming.
74 * @param {string} text
75 * @returns {string}
76 */
77export function trimTrailingWhitespacePlusSpace(text) {
78 // Consense multiple leading and trailing newlines into one newline
79 // Trim trailing whitespace excluding newlines
80 return text.replaceAll(/(\n+$|^\n+)/g, '\n').replaceAll(/[^\S\n]+$/g, ' ');
81}