|
| 1 | +use crate::semantic_services::Semantic; |
| 2 | +use crate::JsRuleAction; |
| 3 | +use rome_analyze::context::RuleContext; |
| 4 | +use rome_analyze::{declare_rule, ActionCategory, Rule, RuleDiagnostic}; |
| 5 | +use rome_console::markup; |
| 6 | +use rome_diagnostics::Applicability; |
| 7 | +use rome_js_factory::{make, syntax::T}; |
| 8 | +use rome_js_syntax::{ |
| 9 | + AnyJsExpression, JsBinaryOperator, JsCallExpression, JsClassDeclaration, JsClassExpression, |
| 10 | + JsExtendsClause, JsInExpression, OperatorPrecedence, |
| 11 | +}; |
| 12 | +use rome_rowan::{AstNode, AstSeparatedList, BatchMutationExt}; |
| 13 | + |
| 14 | +declare_rule! { |
| 15 | + /// Disallow the use of `Math.pow` in favor of the `**` operator. |
| 16 | + /// |
| 17 | + /// > Introduced in ES2016, the infix exponentiation operator ** is an alternative for the standard Math.pow function. |
| 18 | + /// > Infix notation is considered to be more readable and thus more preferable than the function notation. |
| 19 | + /// |
| 20 | + /// Source: https://eslint.org/docs/latest/rules/prefer-exponentiation-operator |
| 21 | + /// |
| 22 | + /// ## Examples |
| 23 | + /// |
| 24 | + /// ### Invalid |
| 25 | + /// |
| 26 | + /// ```js,expect_diagnostic |
| 27 | + /// const foo = Math.pow(2, 8); |
| 28 | + /// ``` |
| 29 | + /// |
| 30 | + /// ```js,expect_diagnostic |
| 31 | + /// const bar = Math.pow(a, b); |
| 32 | + /// ``` |
| 33 | + /// |
| 34 | + /// ```js,expect_diagnostic |
| 35 | + /// let baz = Math.pow(a + b, c + d); |
| 36 | + /// ``` |
| 37 | + /// |
| 38 | + /// ```js,expect_diagnostic |
| 39 | + /// let quux = Math.pow(-1, n); |
| 40 | + /// ``` |
| 41 | + /// |
| 42 | + /// ### Valid |
| 43 | + /// |
| 44 | + /// ```js |
| 45 | + /// const foo = 2 ** 8; |
| 46 | + /// |
| 47 | + /// const bar = a ** b; |
| 48 | + /// |
| 49 | + /// let baz = (a + b) ** (c + d); |
| 50 | + /// |
| 51 | + /// let quux = (-1) ** n; |
| 52 | + /// ``` |
| 53 | + /// |
| 54 | + pub(crate) UseExponentiationOperator { |
| 55 | + version: "11.0.0", |
| 56 | + name: "useExponentiationOperator", |
| 57 | + recommended: false, |
| 58 | + } |
| 59 | +} |
| 60 | + |
| 61 | +pub struct MathPowCall { |
| 62 | + base: AnyJsExpression, |
| 63 | + exponent: AnyJsExpression, |
| 64 | +} |
| 65 | + |
| 66 | +impl MathPowCall { |
| 67 | + fn make_base(&self) -> Option<AnyJsExpression> { |
| 68 | + Some(if self.does_base_need_parens()? { |
| 69 | + parenthesize_any_js_expression(&self.base) |
| 70 | + } else { |
| 71 | + self.base.clone() |
| 72 | + }) |
| 73 | + } |
| 74 | + |
| 75 | + fn make_exponent(&self) -> Option<AnyJsExpression> { |
| 76 | + Some(if self.does_exponent_need_parens()? { |
| 77 | + parenthesize_any_js_expression(&self.exponent) |
| 78 | + } else { |
| 79 | + self.exponent.clone() |
| 80 | + }) |
| 81 | + } |
| 82 | + |
| 83 | + /// Determines whether the base expression needs parens in an exponentiation binary expression. |
| 84 | + fn does_base_need_parens(&self) -> Option<bool> { |
| 85 | + Some( |
| 86 | + // '**' is right-associative, parens are needed when Math.pow(a ** b, c) is converted to (a ** b) ** c |
| 87 | + self.base.precedence().ok()? <= OperatorPrecedence::Exponential |
| 88 | + // An unary operator cannot be used immediately before an exponentiation expression |
| 89 | + || self.base.as_js_unary_expression().is_some() |
| 90 | + || self.base.as_js_await_expression().is_some(), |
| 91 | + ) |
| 92 | + } |
| 93 | + |
| 94 | + /// Determines whether the exponent expression needs parens in an exponentiation binary expression. |
| 95 | + fn does_exponent_need_parens(&self) -> Option<bool> { |
| 96 | + Some(self.exponent.precedence().ok()? < OperatorPrecedence::Exponential) |
| 97 | + } |
| 98 | +} |
| 99 | + |
| 100 | +impl Rule for UseExponentiationOperator { |
| 101 | + type Query = Semantic<JsCallExpression>; |
| 102 | + type State = (); |
| 103 | + type Signals = Option<Self::State>; |
| 104 | + type Options = (); |
| 105 | + |
| 106 | + fn run(ctx: &RuleContext<Self>) -> Self::Signals { |
| 107 | + let node = ctx.query(); |
| 108 | + let model = ctx.model(); |
| 109 | + |
| 110 | + let object = match node.callee().ok()?.omit_parentheses() { |
| 111 | + AnyJsExpression::JsStaticMemberExpression(static_member_expr) => { |
| 112 | + if static_member_expr |
| 113 | + .member() |
| 114 | + .ok()? |
| 115 | + .as_js_name()? |
| 116 | + .value_token() |
| 117 | + .ok()? |
| 118 | + .token_text_trimmed() |
| 119 | + != "pow" |
| 120 | + { |
| 121 | + return None; |
| 122 | + } |
| 123 | + |
| 124 | + static_member_expr.object() |
| 125 | + } |
| 126 | + AnyJsExpression::JsComputedMemberExpression(computed_member_expr) => { |
| 127 | + if !computed_member_expr |
| 128 | + .member() |
| 129 | + .ok()? |
| 130 | + .is_string_constant("pow") |
| 131 | + { |
| 132 | + return None; |
| 133 | + } |
| 134 | + |
| 135 | + computed_member_expr.object() |
| 136 | + } |
| 137 | + _ => return None, |
| 138 | + }; |
| 139 | + |
| 140 | + let reference = object.ok()?.omit_parentheses().as_reference_identifier()?; |
| 141 | + |
| 142 | + // verifies that the Math reference is not a local variable |
| 143 | + let has_math_pow = reference.has_name("Math") && model.binding(&reference).is_none(); |
| 144 | + has_math_pow.then_some(()) |
| 145 | + } |
| 146 | + |
| 147 | + fn diagnostic(ctx: &RuleContext<Self>, _: &Self::State) -> Option<RuleDiagnostic> { |
| 148 | + let diagnostic = RuleDiagnostic::new( |
| 149 | + rule_category!(), |
| 150 | + ctx.query().range(), |
| 151 | + "Use the '**' operator instead of 'Math.pow'.", |
| 152 | + ); |
| 153 | + |
| 154 | + Some(diagnostic) |
| 155 | + } |
| 156 | + |
| 157 | + fn action(ctx: &RuleContext<Self>, _: &Self::State) -> Option<JsRuleAction> { |
| 158 | + let node = ctx.query(); |
| 159 | + |
| 160 | + if !should_suggest_fix(node)? { |
| 161 | + return None; |
| 162 | + } |
| 163 | + |
| 164 | + let mut mutation = ctx.root().begin(); |
| 165 | + let [base, exponent] = node.get_arguments_by_index([0, 1]); |
| 166 | + |
| 167 | + let math_pow_call = MathPowCall { |
| 168 | + base: base?.as_any_js_expression()?.clone().omit_parentheses(), |
| 169 | + exponent: exponent?.as_any_js_expression()?.clone().omit_parentheses(), |
| 170 | + }; |
| 171 | + |
| 172 | + let new_node = make::js_binary_expression( |
| 173 | + math_pow_call.make_base()?, |
| 174 | + make::token(T![**]), |
| 175 | + math_pow_call.make_exponent()?, |
| 176 | + ); |
| 177 | + |
| 178 | + if let Some((needs_parens, parent)) = does_exponentiation_expression_need_parens(node) { |
| 179 | + if needs_parens && parent.is_some() { |
| 180 | + mutation.replace_node(parent.clone()?, parenthesize_any_js_expression(&parent?)); |
| 181 | + } |
| 182 | + |
| 183 | + mutation.replace_node( |
| 184 | + AnyJsExpression::from(node.clone()), |
| 185 | + parenthesize_any_js_expression(&AnyJsExpression::from(new_node)), |
| 186 | + ); |
| 187 | + } else { |
| 188 | + mutation.replace_node( |
| 189 | + AnyJsExpression::from(node.clone()), |
| 190 | + AnyJsExpression::from(new_node), |
| 191 | + ); |
| 192 | + } |
| 193 | + |
| 194 | + Some(JsRuleAction { |
| 195 | + category: ActionCategory::QuickFix, |
| 196 | + applicability: Applicability::MaybeIncorrect, |
| 197 | + message: markup! { "Use the '**' operator instead of 'Math.pow'." }.to_owned(), |
| 198 | + mutation, |
| 199 | + }) |
| 200 | + } |
| 201 | +} |
| 202 | + |
| 203 | +/// Verify if the autofix is safe to be applied and won't remove comments. |
| 204 | +/// Argument list is considered valid if there's no spread arg and leading/trailing comments. |
| 205 | +fn should_suggest_fix(node: &JsCallExpression) -> Option<bool> { |
| 206 | + let arguments = node.arguments().ok()?; |
| 207 | + let args_count = arguments.args().len(); |
| 208 | + |
| 209 | + Some( |
| 210 | + args_count == 2 |
| 211 | + && !arguments.l_paren_token().ok()?.has_leading_comments() |
| 212 | + && !arguments.l_paren_token().ok()?.has_trailing_comments() |
| 213 | + && !arguments.r_paren_token().ok()?.has_leading_comments() |
| 214 | + && !arguments.r_paren_token().ok()?.has_trailing_comments() |
| 215 | + && arguments.args().into_iter().flatten().all(|arg| { |
| 216 | + !arg.syntax().has_leading_comments() |
| 217 | + && !arg.syntax().has_trailing_comments() |
| 218 | + && arg.as_js_spread().is_none() |
| 219 | + }), |
| 220 | + ) |
| 221 | +} |
| 222 | + |
| 223 | +/// Wraps a [AnyJsExpression] in paretheses |
| 224 | +fn parenthesize_any_js_expression(expr: &AnyJsExpression) -> AnyJsExpression { |
| 225 | + AnyJsExpression::from(make::js_parenthesized_expression( |
| 226 | + make::token(T!['(']), |
| 227 | + expr.clone(), |
| 228 | + make::token(T![')']), |
| 229 | + )) |
| 230 | +} |
| 231 | + |
| 232 | +/// Determines whether the given parent node needs parens if used as the exponent in an exponentiation binary expression. |
| 233 | +fn does_exponentiation_expression_need_parens( |
| 234 | + node: &JsCallExpression, |
| 235 | +) -> Option<(bool, Option<AnyJsExpression>)> { |
| 236 | + if let Some(parent) = node.parent::<AnyJsExpression>() { |
| 237 | + if does_expression_need_parens(node, &parent)? { |
| 238 | + return Some((true, Some(parent))); |
| 239 | + } |
| 240 | + } else if let Some(extends_clause) = node.parent::<JsExtendsClause>() { |
| 241 | + if extends_clause.parent::<JsClassDeclaration>().is_some() { |
| 242 | + return Some((true, None)); |
| 243 | + } |
| 244 | + |
| 245 | + if let Some(class_expr) = extends_clause.parent::<JsClassExpression>() { |
| 246 | + let class_expr = AnyJsExpression::from(class_expr); |
| 247 | + if does_expression_need_parens(node, &class_expr)? { |
| 248 | + return Some((true, Some(class_expr))); |
| 249 | + } |
| 250 | + } |
| 251 | + } |
| 252 | + |
| 253 | + None |
| 254 | +} |
| 255 | + |
| 256 | +/// Determines whether the given expression needs parens when used in an exponentiation binary expression. |
| 257 | +fn does_expression_need_parens( |
| 258 | + node: &JsCallExpression, |
| 259 | + expression: &AnyJsExpression, |
| 260 | +) -> Option<bool> { |
| 261 | + let needs_parentheses = match &expression { |
| 262 | + // Skips already parenthesized expressions |
| 263 | + AnyJsExpression::JsParenthesizedExpression(_) => return None, |
| 264 | + AnyJsExpression::JsBinaryExpression(bin_expr) => { |
| 265 | + if bin_expr.parent::<JsInExpression>().is_some() { |
| 266 | + return Some(true); |
| 267 | + } |
| 268 | + |
| 269 | + let binding = bin_expr.right().ok()?; |
| 270 | + let call_expr = binding.as_js_call_expression(); |
| 271 | + |
| 272 | + bin_expr.operator().ok()? != JsBinaryOperator::Exponent |
| 273 | + || call_expr.is_none() |
| 274 | + || call_expr? != node |
| 275 | + } |
| 276 | + AnyJsExpression::JsCallExpression(call_expr) => !call_expr |
| 277 | + .arguments() |
| 278 | + .ok()? |
| 279 | + .args() |
| 280 | + .iter() |
| 281 | + .filter_map(|arg| { |
| 282 | + let binding = arg.ok()?; |
| 283 | + return binding |
| 284 | + .as_any_js_expression()? |
| 285 | + .as_js_call_expression() |
| 286 | + .cloned(); |
| 287 | + }) |
| 288 | + .any(|arg| &arg == node), |
| 289 | + AnyJsExpression::JsNewExpression(new_expr) => !new_expr |
| 290 | + .arguments()? |
| 291 | + .args() |
| 292 | + .iter() |
| 293 | + .filter_map(|arg| { |
| 294 | + let binding = arg.ok()?; |
| 295 | + return binding |
| 296 | + .as_any_js_expression()? |
| 297 | + .as_js_call_expression() |
| 298 | + .cloned(); |
| 299 | + }) |
| 300 | + .any(|arg| &arg == node), |
| 301 | + AnyJsExpression::JsComputedMemberExpression(member_expr) => { |
| 302 | + let binding = member_expr.member().ok()?; |
| 303 | + let call_expr = binding.as_js_call_expression(); |
| 304 | + |
| 305 | + call_expr.is_none() || call_expr? != node |
| 306 | + } |
| 307 | + AnyJsExpression::JsInExpression(_) => return Some(true), |
| 308 | + AnyJsExpression::JsClassExpression(_) |
| 309 | + | AnyJsExpression::JsStaticMemberExpression(_) |
| 310 | + | AnyJsExpression::JsUnaryExpression(_) |
| 311 | + | AnyJsExpression::JsTemplateExpression(_) => true, |
| 312 | + _ => false, |
| 313 | + }; |
| 314 | + |
| 315 | + Some(needs_parentheses && expression.precedence().ok()? >= OperatorPrecedence::Exponential) |
| 316 | +} |
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