swc_ecma_codegen/
decl.rs

1use swc_common::{SourceMapper, Spanned};
2use swc_ecma_ast::*;
3use swc_ecma_codegen_macros::emitter;
4
5use super::{Emitter, Result};
6use crate::text_writer::WriteJs;
7
8impl<W, S: SourceMapper> Emitter<'_, W, S>
9where
10    W: WriteJs,
11    S: SourceMapperExt,
12{
13    #[emitter]
14    fn emit_decl(&mut self, node: &Decl) -> Result {
15        match node {
16            Decl::Class(ref n) => emit!(n),
17            Decl::Fn(ref n) => emit!(n),
18
19            Decl::Var(ref n) => {
20                self.emit_var_decl_inner(n)?;
21                formatting_semi!();
22                srcmap!(n, false);
23            }
24            Decl::Using(n) => emit!(n),
25            Decl::TsEnum(ref n) => emit!(n),
26            Decl::TsInterface(ref n) => emit!(n),
27            Decl::TsModule(ref n) => emit!(n),
28            Decl::TsTypeAlias(ref n) => emit!(n),
29        }
30    }
31
32    #[emitter]
33    fn emit_class_decl(&mut self, node: &ClassDecl) -> Result {
34        self.emit_class_decl_inner(node, false)?;
35    }
36
37    #[emitter]
38    fn emit_using_decl(&mut self, node: &UsingDecl) -> Result {
39        self.emit_leading_comments_of_span(node.span(), false)?;
40
41        if node.is_await {
42            keyword!("await");
43            space!();
44        }
45
46        keyword!("using");
47        space!();
48
49        self.emit_list(
50            node.span,
51            Some(&node.decls),
52            ListFormat::VariableDeclarationList,
53        )?;
54    }
55
56    pub(super) fn emit_class_decl_inner(
57        &mut self,
58        node: &ClassDecl,
59        skip_decorators: bool,
60    ) -> Result {
61        self.emit_leading_comments_of_span(node.span(), false)?;
62
63        srcmap!(self, node, true);
64
65        if node.declare {
66            keyword!(self, "declare");
67            space!(self);
68        }
69
70        if !skip_decorators {
71            for dec in &node.class.decorators {
72                emit!(self, dec);
73            }
74        }
75
76        if node.class.is_abstract {
77            keyword!(self, "abstract");
78            space!(self);
79        }
80
81        keyword!(self, "class");
82        space!(self);
83        emit!(self, node.ident);
84        emit!(self, node.class.type_params);
85
86        self.emit_class_trailing(&node.class)?;
87
88        Ok(())
89    }
90
91    #[emitter]
92    fn emit_fn_decl(&mut self, node: &FnDecl) -> Result {
93        self.emit_leading_comments_of_span(node.span(), false)?;
94
95        self.wr.commit_pending_semi()?;
96
97        srcmap!(node, true);
98
99        if node.declare {
100            keyword!("declare");
101            space!();
102        }
103
104        if node.function.is_async {
105            keyword!("async");
106            space!();
107        }
108
109        keyword!("function");
110        if node.function.is_generator {
111            punct!("*");
112            formatting_space!();
113        } else {
114            space!();
115        }
116
117        emit!(node.ident);
118
119        self.emit_fn_trailing(&node.function)?;
120    }
121
122    #[emitter]
123    fn emit_var_decl(&mut self, node: &VarDecl) -> Result {
124        self.emit_var_decl_inner(node)?;
125    }
126
127    fn emit_var_decl_inner(&mut self, node: &VarDecl) -> Result {
128        self.emit_leading_comments_of_span(node.span, false)?;
129
130        self.wr.commit_pending_semi()?;
131
132        srcmap!(self, node, true);
133
134        if node.declare {
135            keyword!(self, "declare");
136            space!(self);
137        }
138
139        keyword!(self, node.kind.as_str());
140
141        let starts_with_ident = match node.decls.first() {
142            Some(VarDeclarator {
143                name: Pat::Array(..) | Pat::Rest(..) | Pat::Object(..),
144                ..
145            }) => false,
146            _ => true,
147        };
148        if starts_with_ident {
149            space!(self);
150        } else {
151            formatting_space!(self);
152        }
153
154        self.emit_list(
155            node.span(),
156            Some(&node.decls),
157            ListFormat::VariableDeclarationList,
158        )?;
159
160        Ok(())
161    }
162
163    #[emitter]
164    fn emit_var_declarator(&mut self, node: &VarDeclarator) -> Result {
165        self.emit_leading_comments_of_span(node.span(), false)?;
166
167        srcmap!(node, true);
168
169        emit!(node.name);
170
171        if let Some(ref init) = node.init {
172            formatting_space!();
173            punct!("=");
174            formatting_space!();
175            emit!(init);
176        }
177    }
178}
179
180#[cfg(test)]
181mod tests {
182    use crate::tests::assert_min;
183
184    #[test]
185    fn issue_275() {
186        assert_min(
187            "function* foo(){
188            yield getServiceHosts()
189        }",
190            "function*foo(){yield getServiceHosts()}",
191        );
192    }
193
194    #[test]
195    fn issue_1764() {
196        assert_min(
197            "class Hoge {};
198class HogeFuga extends Hoge {};",
199            "class Hoge{};class HogeFuga extends Hoge{};",
200        );
201    }
202
203    #[test]
204    fn single_argument_arrow_expression() {
205        assert_min("function* f(){ yield x => x}", "function*f(){yield x=>x}");
206        assert_min(
207            "function* f(){ yield ({x}) => x}",
208            "function*f(){yield({x})=>x}",
209        );
210    }
211
212    #[test]
213    fn class_static_block() {
214        assert_min("class Foo { static { 1 + 1; }}", "class Foo{static{1+1}}");
215    }
216}
swc_ecma_codegen/decl.rs

swc_ecma_codegen/
decl.rs
