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'use strict';
const isFullwidthCodePoint = require('is-fullwidth-code-point');
const astralRegex = require('astral-regex');
const ansiStyles = require('ansi-styles');
const ESCAPES = [
'\u001B',
'\u009B'
];
const wrapAnsi = code => `${ESCAPES[0]}[${code}m`;
const checkAnsi = (ansiCodes, isEscapes, endAnsiCode) => {
let output = [];
ansiCodes = [...ansiCodes];
for (let ansiCode of ansiCodes) {
const ansiCodeOrigin = ansiCode;
if (ansiCode.includes(';')) {
ansiCode = ansiCode.split(';')[0][0] + '0';
}
const item = ansiStyles.codes.get(Number.parseInt(ansiCode, 10));
if (item) {
const indexEscape = ansiCodes.indexOf(item.toString());
if (indexEscape === -1) {
output.push(wrapAnsi(isEscapes ? item : ansiCodeOrigin));
} else {
ansiCodes.splice(indexEscape, 1);
}
} else if (isEscapes) {
output.push(wrapAnsi(0));
break;
} else {
output.push(wrapAnsi(ansiCodeOrigin));
}
}
if (isEscapes) {
output = output.filter((element, index) => output.indexOf(element) === index);
if (endAnsiCode !== undefined) {
const fistEscapeCode = wrapAnsi(ansiStyles.codes.get(Number.parseInt(endAnsiCode, 10)));
output = output.reduce((current, next) => next === fistEscapeCode ? [next, ...current] : [...current, next], []);
}
}
return output.join('');
};
module.exports = (string, begin, end) => {
const characters = [...string];
const ansiCodes = [];
let stringEnd = typeof end === 'number' ? end : characters.length;
let isInsideEscape = false;
let ansiCode;
let visible = 0;
let output = '';
for (const [index, character] of characters.entries()) {
let leftEscape = false;
if (ESCAPES.includes(character)) {
const code = /\d[^m]*/.exec(string.slice(index, index + 18));
ansiCode = code && code.length > 0 ? code[0] : undefined;
if (visible < stringEnd) {
isInsideEscape = true;
if (ansiCode !== undefined) {
ansiCodes.push(ansiCode);
}
}
} else if (isInsideEscape && character === 'm') {
isInsideEscape = false;
leftEscape = true;
}
if (!isInsideEscape && !leftEscape) {
visible++;
}
if (!astralRegex({exact: true}).test(character) && isFullwidthCodePoint(character.codePointAt())) {
visible++;
if (typeof end !== 'number') {
stringEnd++;
}
}
if (visible > begin && visible <= stringEnd) {
output += character;
} else if (visible === begin && !isInsideEscape && ansiCode !== undefined) {
output = checkAnsi(ansiCodes);
} else if (visible >= stringEnd) {
output += checkAnsi(ansiCodes, true, ansiCode);
break;
}
}
return output;
};