| 'use strict'; |
| const isFullwidthCodePoint = require('is-fullwidth-code-point'); |
| |
| const ESCAPES = [ |
| '\u001B', |
| '\u009B' |
| ]; |
| |
| const END_CODE = 39; |
| const ASTRAL_REGEX = /[\uD800-\uDBFF][\uDC00-\uDFFF]/; |
| |
| const ESCAPE_CODES = new Map([ |
| [0, 0], |
| [1, 22], |
| [2, 22], |
| [3, 23], |
| [4, 24], |
| [7, 27], |
| [8, 28], |
| [9, 29], |
| [30, 39], |
| [31, 39], |
| [32, 39], |
| [33, 39], |
| [34, 39], |
| [35, 39], |
| [36, 39], |
| [37, 39], |
| [90, 39], |
| [40, 49], |
| [41, 49], |
| [42, 49], |
| [43, 49], |
| [44, 49], |
| [45, 49], |
| [46, 49], |
| [47, 49] |
| ]); |
| |
| const wrapAnsi = code => `${ESCAPES[0]}[${code}m`; |
| |
| module.exports = (str, begin, end) => { |
| const arr = Array.from(str.normalize()); |
| |
| end = typeof end === 'number' ? end : arr.length; |
| |
| let insideEscape = false; |
| let escapeCode; |
| let visible = 0; |
| let output = ''; |
| |
| for (const item of arr.entries()) { |
| const i = item[0]; |
| const x = item[1]; |
| |
| let leftEscape = false; |
| |
| if (ESCAPES.indexOf(x) !== -1) { |
| insideEscape = true; |
| const code = /\d[^m]*/.exec(str.slice(i, i + 4)); |
| escapeCode = code === END_CODE ? null : code; |
| } else if (insideEscape && x === 'm') { |
| insideEscape = false; |
| leftEscape = true; |
| } |
| |
| if (!insideEscape && !leftEscape) { |
| ++visible; |
| } |
| |
| if (!ASTRAL_REGEX.test(x) && isFullwidthCodePoint(x.codePointAt())) { |
| ++visible; |
| } |
| |
| if (visible > begin && visible <= end) { |
| output += x; |
| } else if (visible === begin && !insideEscape && escapeCode !== undefined && escapeCode !== END_CODE) { |
| output += wrapAnsi(escapeCode); |
| } else if (visible >= end) { |
| if (escapeCode !== undefined) { |
| output += wrapAnsi(ESCAPE_CODES.get(parseInt(escapeCode, 10)) || END_CODE); |
| } |
| break; |
| } |
| } |
| |
| return output; |
| }; |