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LibJS: Function.length respects default and rest parameters

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"[Function.length is] the number of formal parameters. This number
excludes the rest parameter and only includes parameters before
the first one with a default value." - MDN
This commit is contained in:
Matthew Olsson 2020-05-05 20:02:14 -07:00 • committed by Andreas Kling
parent 2c14714ee0
commit 838390171c
6 changed files with 43 additions and 15 deletions
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17
Libraries/LibJS/Parser.cpp
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@ -285,6 +285,7 @@ RefPtr<FunctionExpression> Parser::try_parse_arrow_function_expression(bool expe
Vector<FunctionNode::Parameter> parameters;
bool parse_failed = false;
bool has_rest_parameter = false;
i32 function_length = -1;
while (true) {
if (match(TokenType::Comma)) {
if (has_rest_parameter) {
@ -297,6 +298,7 @@ RefPtr<FunctionExpression> Parser::try_parse_arrow_function_expression(bool expe
RefPtr<Expression> default_value;
if (expect_parens && match(TokenType::Equals)) {
consume(TokenType::Equals);
function_length = parameters.size();
default_value = parse_expression(0);
}
parameters.append({ parameter_name, default_value });
@ -307,6 +309,7 @@ RefPtr<FunctionExpression> Parser::try_parse_arrow_function_expression(bool expe
break;
}
has_rest_parameter = true;
function_length = parameters.size();
auto parameter_name = consume(TokenType::Identifier).value();
parameters.append({ parameter_name, nullptr, true });
} else if (match(TokenType::ParenClose)) {
@ -337,6 +340,9 @@ RefPtr<FunctionExpression> Parser::try_parse_arrow_function_expression(bool expe
if (parse_failed)
return nullptr;
if (function_length == -1)
function_length = parameters.size();
auto function_body_result = [this]() -> RefPtr<BlockStatement> {
if (match(TokenType::CurlyOpen)) {
// Parse a function body with statements
@ -361,7 +367,7 @@ RefPtr<FunctionExpression> Parser::try_parse_arrow_function_expression(bool expe
if (!function_body_result.is_null()) {
state_rollback_guard.disarm();
auto body = function_body_result.release_nonnull();
return create_ast_node<FunctionExpression>("", move(body), move(parameters), m_parser_state.m_var_scopes.take_last());
return create_ast_node<FunctionExpression>("", move(body), move(parameters), function_length, m_parser_state.m_var_scopes.take_last());
}
return nullptr;
@ -863,10 +869,12 @@ NonnullRefPtr<FunctionNodeType> Parser::parse_function_node(bool needs_function_
}
consume(TokenType::ParenOpen);
Vector<FunctionNode::Parameter> parameters;
i32 function_length = -1;
while (match(TokenType::Identifier) || match(TokenType::TripleDot)) {
if (match(TokenType::TripleDot)) {
consume();
auto parameter_name = consume(TokenType::Identifier).value();
function_length = parameters.size();
parameters.append({ parameter_name, nullptr, true });
break;
}
@ -874,6 +882,7 @@ NonnullRefPtr<FunctionNodeType> Parser::parse_function_node(bool needs_function_
RefPtr<Expression> default_value;
if (match(TokenType::Equals)) {
consume(TokenType::Equals);
function_length = parameters.size();
default_value = parse_expression(0);
}
parameters.append({ parameter_name, default_value });
@ -882,9 +891,13 @@ NonnullRefPtr<FunctionNodeType> Parser::parse_function_node(bool needs_function_
consume(TokenType::Comma);
}
consume(TokenType::ParenClose);
if (function_length == -1)
function_length = parameters.size();
auto body = parse_block_statement();
body->add_variables(m_parser_state.m_var_scopes.last());
return create_ast_node<FunctionNodeType>(name, move(body), move(parameters), NonnullRefPtrVector<VariableDeclaration>());
return create_ast_node<FunctionNodeType>(name, move(body), move(parameters), function_length, NonnullRefPtrVector<VariableDeclaration>());
}
NonnullRefPtr<VariableDeclaration> Parser::parse_variable_declaration()