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perf: faster strip_html #440

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Merged
D-Sketon merged 4 commits into from
Oct 3, 2025
Merged

perf: faster strip_html #440

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32aff62
perf: faster strip_html
D-Sketon Oct 2, 2025
afd2fb2
Merge branch 'master' into perf/3.3.0-1
D-Sketon Oct 2, 2025
62b496f
perf: use number as state
D-Sketon Oct 2, 2025
0e85418
Merge branch 'perf/3.3.0-1' of github.com:hexojs/hexo-util into perf/…
D-Sketon Oct 2, 2025
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159 changes: 69 additions & 90 deletions lib/strip_html.ts
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Original file line number Diff line number Diff line change
@@ -1,6 +1,15 @@
const STATE_PLAINTEXT = Symbol('plaintext');
const STATE_HTML = Symbol('html');
const STATE_COMMENT = Symbol('comment');
const STATE_PLAINTEXT = 0;
const STATE_HTML = 1;
const STATE_COMMENT = 2;

const CHAR_LT = 60; // '<'
const CHAR_GT = 62; // '>'
const CHAR_QUOTE = 34; // '"'
const CHAR_APOS = 39; // "'"
const CHAR_DASH = 45; // '-'
const CHAR_SPACE = 32; // ' '
const CHAR_NEWLINE = 10; // '\n'
const CHAR_EXCLAIM = 33; // '!'

// eslint-disable-next-line @typescript-eslint/ban-types
function striptags(html: string | String = '') {
Expand All @@ -10,114 +19,84 @@ function striptags(html: string | String = '') {
}

let state = STATE_PLAINTEXT;
let tag_buffer = '';
let depth = 0;
let in_quote_char = '';
let in_quote_char = 0;
let output = '';
let tag_start = -1;
let plain_text_start = 0;

const { length } = html;

for (let idx = 0; idx < length; idx++) {
const char = html[idx];
const charCode = html.charCodeAt(idx);

if (state === STATE_PLAINTEXT) {
switch (char) {
case '<':
state = STATE_HTML;
tag_buffer = tag_buffer + char;
break;

default:
output += char;
break;
if (charCode === CHAR_LT) {
output += html.slice(plain_text_start, idx);
state = STATE_HTML;
tag_start = idx;
}
} else if (state === STATE_HTML) {
switch (char) {
case '<':
// ignore '<' if inside a quote
if (in_quote_char) break;

// we're seeing a nested '<'
depth++;
break;

case '>':
// ignore '>' if inside a quote
if (in_quote_char) {
break;
}

// something like this is happening: '<<>>'
if (charCode === CHAR_LT) {
// ignore '<' if inside a quote
if (!in_quote_char) depth++;
} else if (charCode === CHAR_GT) {
// ignore '>' if inside a quote
if (!in_quote_char) {
if (depth) {
depth--;

break;
}

// this is closing the tag in tag_buffer
in_quote_char = '';
state = STATE_PLAINTEXT;
// tag_buffer += '>';

tag_buffer = '';
break;

case '"':
case '\'':
// catch both single and double quotes

if (char === in_quote_char) {
in_quote_char = '';
} else {
in_quote_char = in_quote_char || char;
}

tag_buffer = tag_buffer + char;
break;

case '-':
if (tag_buffer === '<!-') {
state = STATE_COMMENT;
}

tag_buffer = tag_buffer + char;
break;

case ' ':
case '\n':
if (tag_buffer === '<') {
// this is closing the tag in tag_buffer
in_quote_char = 0;
state = STATE_PLAINTEXT;
output += '< ';
tag_buffer = '';

break;
tag_start = -1;
plain_text_start = idx + 1;
}

tag_buffer = tag_buffer + char;
break;

default:
tag_buffer = tag_buffer + char;
break;
}
} else if (charCode === CHAR_QUOTE || charCode === CHAR_APOS) {
// catch both single and double quotes

if (charCode === in_quote_char) {
in_quote_char = 0;
} else {
in_quote_char = in_quote_char || charCode;
}
} else if (charCode === CHAR_DASH) {
// same as if (html.slice(tag_start, idx) === '<!-') {
if (idx - tag_start === 3
&& html.charCodeAt(tag_start + 1) === CHAR_EXCLAIM
&& html.charCodeAt(tag_start + 2) === CHAR_DASH
) {
state = STATE_COMMENT;
}
} else if (charCode === CHAR_SPACE || charCode === CHAR_NEWLINE) {
// same as if (html.slice(tag_start, idx) === '<') {
if (idx - tag_start === 1) {
state = STATE_PLAINTEXT;
output += '< ';
tag_start = -1;
plain_text_start = idx + 1;
}
}
} else if (state === STATE_COMMENT) {
switch (char) {
case '>':
if (tag_buffer.slice(-2) === '--') {
// close the comment
state = STATE_PLAINTEXT;
}

tag_buffer = '';
break;

default:
tag_buffer = tag_buffer + char;
break;
if (charCode === CHAR_GT) {
// same as if (html.slice(idx - 2, idx) === '--') {
if (idx >= 2
&& html.charCodeAt(idx - 1) === CHAR_DASH
&& html.charCodeAt(idx - 2) === CHAR_DASH) {
// close the comment
state = STATE_PLAINTEXT;
plain_text_start = idx + 1;
}
tag_start = -1;
}
}
}

if (state === STATE_PLAINTEXT && plain_text_start < length) {
output += html.slice(plain_text_start);
}

return output;
}

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