Skip to content

perf: shave off some bytes by using peek() more often #105

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
bartveneman merged 1 commit into from
Jan 3, 2026
Merged

perf: shave off some bytes by using peek() more often #105

Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
17 changes: 7 additions & 10 deletions src/tokenize.ts
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -158,7 +158,7 @@ export class Lexer {
this.advance(2) // Skip /*
while (this.pos < this.source.length - 1) {
let ch = this.source.charCodeAt(this.pos)
if (ch === CHAR_ASTERISK && this.source.charCodeAt(this.pos + 1) === CHAR_FORWARD_SLASH) {
if (ch === CHAR_ASTERISK && this.peek() === CHAR_FORWARD_SLASH) {
this.advance(2)
break
}
Expand All @@ -179,25 +179,22 @@ export class Lexer {
if (is_digit(ch)) {
return this.consume_number(start_line, start_column)
}

if (ch === CHAR_DOT && is_digit(this.peek())) {
return this.consume_number(start_line, start_column)
}

// CDO: <!--
if (ch === CHAR_LESS_THAN && this.pos + 3 < this.source.length) {
if (
this.source.charCodeAt(this.pos + 1) === CHAR_EXCLAMATION &&
this.source.charCodeAt(this.pos + 2) === CHAR_HYPHEN &&
this.source.charCodeAt(this.pos + 3) === CHAR_HYPHEN
) {
if (this.peek() === CHAR_EXCLAMATION && this.peek(2) === CHAR_HYPHEN && this.peek(3) === CHAR_HYPHEN) {
this.advance(4)
return this.make_token(TOKEN_CDO, start, this.pos, start_line, start_column)
}
}

// CDC: -->
if (ch === CHAR_HYPHEN && this.pos + 2 < this.source.length) {
if (this.source.charCodeAt(this.pos + 1) === CHAR_HYPHEN && this.source.charCodeAt(this.pos + 2) === CHAR_GREATER_THAN) {
if (this.peek() === CHAR_HYPHEN && this.peek(2) === CHAR_GREATER_THAN) {
this.advance(3)
return this.make_token(TOKEN_CDC, start, this.pos, start_line, start_column)
}
Expand Down Expand Up @@ -263,7 +260,7 @@ export class Lexer {

while (this.pos < this.source.length - 1) {
let ch = this.source.charCodeAt(this.pos)
if (ch === CHAR_ASTERISK && this.source.charCodeAt(this.pos + 1) === CHAR_FORWARD_SLASH) {
if (ch === CHAR_ASTERISK && this.peek() === CHAR_FORWARD_SLASH) {
this.advance(2)
break
}
Expand Down Expand Up @@ -353,7 +350,7 @@ export class Lexer {
this.pos < this.source.length &&
this.source.charCodeAt(this.pos) === CHAR_DOT &&
this.pos + 1 < this.source.length &&
is_digit(this.source.charCodeAt(this.pos + 1))
is_digit(this.peek())
) {
this.advance() // .
while (this.pos < this.source.length && is_digit(this.source.charCodeAt(this.pos))) {
Expand Down Expand Up @@ -412,7 +409,7 @@ export class Lexer {
// Check what follows the backslash before consuming it
if (this.pos + 1 >= this.source.length) break

let next = this.source.charCodeAt(this.pos + 1)
let next = this.peek()

// If followed by newline, it's invalid, stop without consuming backslash
if (is_newline(next)) break
Expand Down