graphql_minify/
minify.rs

1use crate::lexer::{LexingError, Token};
2use logos::Logos;
3
4/// Strips characters that are not significant to the validity or execution of a GraphQL document.
5/// It is functionally equivalent to [`stripIgnoredCharacters`](https://graphql-js.org/api/function/stripignoredcharacters/) defined in the [GraphQL spec](https://spec.graphql.org/June2018/#sec-Source-Text.Ignored-Tokens).
6///
7/// This function takes a value that implements the `AsRef<str>` trait, allowing for flexible input types
8/// that can be treated as a string slice. It returns a `Result` with the minified string or an error
9/// if the lexing process fails.
10///
11/// # Examples
12///
13/// ```
14/// use graphql_minify::minify;
15///
16/// let original = r#"
17/// query SomeQuery($foo: String!, $bar: String) {
18///   someField(foo: $foo, bar: $bar) {
19///    ...fragmented
20///  }
21/// }
22/// "#;
23/// let minified = minify(original).unwrap();
24///
25/// assert_eq!(minified, "query SomeQuery($foo:String!$bar:String){someField(foo:$foo bar:$bar){...fragmented}}");
26/// ```
27///
28/// # Errors
29///
30/// This function will return an error if the lexing process encounters an unexpected character.
31///
32/// # Panics
33///
34/// This function does not panic.
35///
36/// # Safety
37///
38/// This function does not use any unsafe code.
39pub fn minify<T: AsRef<str>>(value: T) -> Result<String, LexingError> {
40  let mut lexer = Token::lexer(value.as_ref());
41  let mut result = String::new();
42  let mut last_token = None;
43
44  while let Some(token) = lexer.next() {
45    let token = match token {
46      Ok(token) => token,
47      Err(e) => return Err(e),
48    };
49
50    if needs_space(&token, &last_token) {
51      result.push(' ');
52    }
53
54    match token {
55      Token::BlockStringDelimiter => result.push_str(&token.parse_block_string(&mut lexer)),
56      _ => result.push_str(lexer.slice()),
57    }
58    last_token = Some(token);
59  }
60
61  Ok(result)
62}
63
64fn is_non_punctuator(token: &Token) -> bool {
65  !matches!(
66    token,
67    Token::BraceOpen
68      | Token::BraceClose
69      | Token::ParenOpen
70      | Token::ParenClose
71      | Token::BracketOpen
72      | Token::BracketClose
73      | Token::Colon
74      | Token::Equals
75      | Token::Exclamation
76      | Token::Question
77      | Token::Ellipsis
78      | Token::Ampersand
79      | Token::Pipe
80      | Token::Variable(_)
81      | Token::Directive(_)
82  )
83}
84
85fn needs_space_after_token(token: &Token) -> bool {
86  matches!(
87    token,
88    Token::Variable(_) | Token::String(_) | Token::Identifier(_) | Token::Directive(_)
89  )
90}
91
92fn needs_space_before_token(token: &Token) -> bool {
93  matches!(
94    token,
95    Token::Identifier(_) | Token::BlockStringDelimiter | Token::Ellipsis
96  )
97}
98
99fn needs_space(curr_token: &Token, last_token: &Option<Token>) -> bool {
100  match last_token {
101    Some(last) if is_non_punctuator(last) => {
102      is_non_punctuator(curr_token) || *curr_token == Token::Ellipsis
103    }
104    Some(last) if needs_space_after_token(last) => needs_space_before_token(curr_token),
105    _ => false,
106  }
107}
108
109#[cfg(test)]
110mod test {
111  use crate::lexer::LexingError;
112  use super::minify;
113  use indoc::indoc;
114
115  #[test]
116  fn strips_ignored_characters_from_graphql_query_document() {
117    let query = indoc! {r#"
118      query SomeQuery($foo: String!, $bar: String) {
119        someField(foo: $foo, bar: $bar) {
120          a
121          b {
122            c
123            d
124          }
125        }
126      }
127    "#};
128
129    let expected =
130      "query SomeQuery($foo:String!$bar:String){someField(foo:$foo bar:$bar){a b{c d}}}";
131
132    assert_eq!(minify(query).unwrap(), expected);
133  }
134
135  #[test]
136  fn strips_ignored_characters_from_graphql_sdl_document() {
137    let sdl = indoc! {r#"
138      """
139      Type description
140      """
141      type Foo {
142        """
143        Field description
144        """
145        bar: String
146      }
147    "#};
148
149    let expected = r#""""Type description""" type Foo{"""Field description""" bar:String}"#;
150
151    assert_eq!(minify(sdl).unwrap(), expected);
152  }
153
154  #[test]
155  fn errs_on_invalid_token() {
156    let query = "{ foo(arg: \"\n\"";
157
158    assert!(matches!(
159      minify(query),
160      Err(LexingError::UnterminatedString(_))
161    ));
162  }
163
164  #[test]
165  fn strips_non_parsable_document() {
166    let query = r#"{ foo(arg: "str""#;
167    let expected = r#"{foo(arg:"str""#;
168
169    assert_eq!(minify(query).unwrap(), expected);
170  }
171
172  #[test]
173  fn strips_documents_with_only_ignored_characters() {
174    assert_eq!(minify("\n").unwrap(), "");
175    assert_eq!(minify(",").unwrap(), "");
176    assert_eq!(minify(",,").unwrap(), "");
177    assert_eq!(minify("#comment\n, \n").unwrap(), "");
178  }
179
180  #[test]
181  fn strips_leading_and_trailing_ignored_tokens() {
182    assert_eq!(minify("\n1").unwrap(), "1");
183    assert_eq!(minify(",1").unwrap(), "1");
184    assert_eq!(minify(",,1").unwrap(), "1");
185    assert_eq!(minify("#comment\n, \n1").unwrap(), "1");
186
187    assert_eq!(minify("1\n").unwrap(), "1");
188    assert_eq!(minify("1,").unwrap(), "1");
189    assert_eq!(minify("1,,").unwrap(), "1");
190    assert_eq!(minify("1#comment\n, \n").unwrap(), "1");
191  }
192
193  #[test]
194  fn strips_ignored_tokens_between_punctuator_tokens() {
195    assert_eq!(minify("[,)").unwrap(), "[)");
196    assert_eq!(minify("[\r)").unwrap(), "[)");
197    assert_eq!(minify("[\r\r)").unwrap(), "[)");
198    assert_eq!(minify("[\r,)").unwrap(), "[)");
199    assert_eq!(minify("[,\n)").unwrap(), "[)");
200  }
201
202  #[test]
203  fn strips_ignored_tokens_between_punctuator_and_non_punctuator_tokens() {
204    assert_eq!(minify("[,1").unwrap(), "[1");
205    assert_eq!(minify("[\r1").unwrap(), "[1");
206    assert_eq!(minify("[\r\r1").unwrap(), "[1");
207    assert_eq!(minify("[\r,1").unwrap(), "[1");
208    assert_eq!(minify("[,\n1").unwrap(), "[1");
209  }
210
211  #[test]
212  fn replace_ignored_tokens_between_non_punctuator_tokens_and_spread_with_space() {
213    assert_eq!(minify("a ...").unwrap(), "a ...");
214    assert_eq!(minify("1 ...").unwrap(), "1 ...");
215    assert_eq!(minify("1 ... ...").unwrap(), "1 ......");
216  }
217
218  #[test]
219  fn replace_ignored_tokens_between_non_punctuator_tokens_with_space() {
220    assert_eq!(minify("1 2").unwrap(), "1 2");
221    assert_eq!(minify("\"\" \"\"").unwrap(), "\"\" \"\"");
222    assert_eq!(minify("a b").unwrap(), "a b");
223
224    assert_eq!(minify("a,1").unwrap(), "a 1");
225    assert_eq!(minify("a,,1").unwrap(), "a 1");
226    assert_eq!(minify("a  1").unwrap(), "a 1");
227    assert_eq!(minify("a \t 1").unwrap(), "a 1");
228  }
229
230  #[test]
231  fn does_not_strip_ignored_tokens_embedded_in_the_string() {
232    assert_eq!(minify("\" \"").unwrap(), "\" \"");
233    assert_eq!(minify("\",\"").unwrap(), "\",\"");
234    assert_eq!(minify("\",,\"").unwrap(), "\",,\"");
235    assert_eq!(minify("\",|\"").unwrap(), "\",|\"");
236  }
237
238  #[test]
239  fn does_not_strip_ignored_tokens_embedded_in_the_block_string() {
240    assert_eq!(minify("\"\"\",\"\"\"").unwrap(), "\"\"\",\"\"\"");
241    assert_eq!(minify("\"\"\",,\"\"\"").unwrap(), "\"\"\",,\"\"\"");
242    assert_eq!(minify("\"\"\",|\"\"\"").unwrap(), "\"\"\",|\"\"\"");
243  }
244
245  #[test]
246  fn strips_ignored_characters_inside_block_strings() {
247    assert_eq!(minify(r#""""""""#).unwrap(), r#""""""""#);
248    assert_eq!(minify(r#"""" """"#).unwrap(), r#""""""""#);
249
250    assert_eq!(minify(r#""""a""""#).unwrap(), r#""""a""""#);
251    assert_eq!(minify(r#"""" a""""#).unwrap(), r#"""" a""""#);
252    assert_eq!(minify(r#"""" a """"#).unwrap(), r#"""" a """"#);
253
254    assert_eq!(minify("\"\"\"\n\"\"\"").unwrap(), r#""""""""#);
255    assert_eq!(minify("\"\"\"a\nb\"\"\"").unwrap(), "\"\"\"a\nb\"\"\"");
256    assert_eq!(minify("\"\"\"a\rb\"\"\"").unwrap(), "\"\"\"a\nb\"\"\"");
257    assert_eq!(minify("\"\"\"a\r\nb\"\"\"").unwrap(), "\"\"\"a\nb\"\"\"");
258    assert_eq!(
259      minify("\"\"\"a\r\n\nb\"\"\"").unwrap(),
260      "\"\"\"a\n\nb\"\"\""
261    );
262
263    assert_eq!(minify("\"\"\"\\\n\"\"\"").unwrap(), "\"\"\"\\\n\"\"\"");
264    assert_eq!(minify("\"\"\"\"\n\"\"\"").unwrap(), "\"\"\"\"\n\"\"\"");
265    assert_eq!(
266      minify("\"\"\"\\\"\"\"\n\"\"\"").unwrap(),
267      "\"\"\"\\\"\"\"\"\"\""
268    );
269
270    assert_eq!(
271      minify("\"\"\"\na\n b\"\"\"").unwrap(),
272      "\"\"\"\na\n b\"\"\""
273    );
274    assert_eq!(minify("\"\"\"\n a\n b\"\"\"").unwrap(), "\"\"\"a\nb\"\"\"");
275    assert_eq!(
276      minify("\"\"\"\na\n b\nc\"\"\"").unwrap(),
277      "\"\"\"a\n b\nc\"\"\""
278    );
279  }
280
281  #[test]
282  fn test_kitchen_sink_query() {
283    let query = include_str!("../data/kitchen_sink_query.gql");
284    let expected = include_str!("../data/kitchen_sink_query_expected.gql");
285
286    assert_eq!(minify(query).unwrap(), expected);
287  }
288
289  #[test]
290  fn test_kitchen_sink_schema() {
291    let schema = include_str!("../data/kitchen_sink_schema.gql");
292    let expected = include_str!("../data/kitchen_sink_schema_expected.gql");
293
294    assert_eq!(minify(schema).unwrap(), expected);
295  }
296}
graphql_minify/minify.rs

graphql_minify/
minify.rs
