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| 1 | +use oxc_ast::{ |
| 2 | + ast::{CallExpression, ChainElement, Expression, MemberExpression}, |
| 3 | + match_member_expression, AstKind, |
| 4 | +}; |
| 5 | +use oxc_diagnostics::OxcDiagnostic; |
| 6 | +use oxc_macros::declare_oxc_lint; |
| 7 | +use oxc_span::cmp::ContentEq; |
| 8 | +use oxc_span::Span; |
| 9 | + |
| 10 | +use crate::{context::LintContext, rule::Rule, AstNode}; |
| 11 | + |
| 12 | +fn no_useless_call_diagnostic(name: &str, span: Span) -> OxcDiagnostic { |
| 13 | + OxcDiagnostic::warn(format!("Avoid unnecessary use of .{name}()")) |
| 14 | + .with_help("Replace with a normal function invocation") |
| 15 | + .with_label(span) |
| 16 | +} |
| 17 | + |
| 18 | +#[derive(Debug, Default, Clone)] |
| 19 | +pub struct NoUselessCall; |
| 20 | + |
| 21 | +declare_oxc_lint!( |
| 22 | + /// ### What it does |
| 23 | + /// Disallow unnecessary calls to `.call()` and `.apply()` |
| 24 | + /// |
| 25 | + /// ### Why is this bad? |
| 26 | + /// `Function.prototype.call()` and `Function.prototype.apply()` are slower than the normal function invocation. |
| 27 | + /// |
| 28 | + /// This rule compares code statically to check whether or not thisArg is changed. |
| 29 | + /// So if the code about thisArg is a dynamic expression, this rule cannot judge correctly. |
| 30 | + /// |
| 31 | + /// ### Examples |
| 32 | + /// |
| 33 | + /// Examples of **incorrect** code for this rule: |
| 34 | + /// ```js |
| 35 | + /// // These are same as `foo(1, 2, 3);` |
| 36 | + /// foo.call(undefined, 1, 2, 3); |
| 37 | + /// foo.apply(undefined, [1, 2, 3]); |
| 38 | + /// foo.call(null, 1, 2, 3); |
| 39 | + /// foo.apply(null, [1, 2, 3]); |
| 40 | + /// |
| 41 | + /// // These are same as `obj.foo(1, 2, 3);` |
| 42 | + /// obj.foo.call(obj, 1, 2, 3); |
| 43 | + /// obj.foo.apply(obj, [1, 2, 3]); |
| 44 | + /// ``` |
| 45 | + /// |
| 46 | + /// Examples of **correct** code for this rule: |
| 47 | + /// ```js |
| 48 | + /// // The `this` binding is different. |
| 49 | + /// foo.call(obj, 1, 2, 3); |
| 50 | + /// foo.apply(obj, [1, 2, 3]); |
| 51 | + /// obj.foo.call(null, 1, 2, 3); |
| 52 | + /// obj.foo.apply(null, [1, 2, 3]); |
| 53 | + /// obj.foo.call(otherObj, 1, 2, 3); |
| 54 | + /// obj.foo.apply(otherObj, [1, 2, 3]); |
| 55 | + /// |
| 56 | + /// // The argument list is variadic. |
| 57 | + /// // Those are warned by the `prefer-spread` rule. |
| 58 | + /// foo.apply(undefined, args); |
| 59 | + /// foo.apply(null, args); |
| 60 | + /// obj.foo.apply(obj, args); |
| 61 | + /// ``` |
| 62 | + NoUselessCall, |
| 63 | + eslint, |
| 64 | + perf |
| 65 | +); |
| 66 | + |
| 67 | +impl Rule for NoUselessCall { |
| 68 | + fn run<'a>(&self, node: &AstNode<'a>, ctx: &LintContext<'a>) { |
| 69 | + let AstKind::CallExpression(call_expr) = node.kind() else { return }; |
| 70 | + |
| 71 | + let Some(callee) = |
| 72 | + as_member_expression_without_chain_expression(call_expr.callee.without_parentheses()) |
| 73 | + else { |
| 74 | + return; |
| 75 | + }; |
| 76 | + |
| 77 | + if !is_call_or_non_variadic_apply(call_expr, callee) { |
| 78 | + return; |
| 79 | + } |
| 80 | + |
| 81 | + let applied = callee.object().without_parentheses(); |
| 82 | + let Some(first_arg) = call_expr.arguments.first() else { return }; |
| 83 | + let Some(this_arg) = first_arg.as_expression() else { return }; |
| 84 | + |
| 85 | + if validate_this_argument(this_arg, applied) { |
| 86 | + ctx.diagnostic(no_useless_call_diagnostic( |
| 87 | + callee.static_property_name().unwrap(), |
| 88 | + call_expr.span, |
| 89 | + )); |
| 90 | + } |
| 91 | + } |
| 92 | +} |
| 93 | + |
| 94 | +fn validate_this_argument(this_arg: &Expression, applied: &Expression) -> bool { |
| 95 | + if this_arg.is_null_or_undefined() { |
| 96 | + return matches!(applied, Expression::Identifier(_)); |
| 97 | + } |
| 98 | + |
| 99 | + let Some(applied_member) = as_member_expression_without_chain_expression(applied) else { |
| 100 | + return false; |
| 101 | + }; |
| 102 | + |
| 103 | + validate_member_expression(this_arg, applied_member) |
| 104 | +} |
| 105 | + |
| 106 | +fn validate_member_expression(this_arg: &Expression, applied_member: &MemberExpression) -> bool { |
| 107 | + let applied_object = applied_member.object().without_parentheses(); |
| 108 | + |
| 109 | + if let Some(this_arg_member) = as_member_expression_without_chain_expression(this_arg) { |
| 110 | + return as_member_expression_without_chain_expression(applied_object).is_some_and( |
| 111 | + |applied_object_member| applied_object_member.content_eq(this_arg_member), |
| 112 | + ); |
| 113 | + } |
| 114 | + |
| 115 | + applied_object.content_eq(this_arg) |
| 116 | +} |
| 117 | + |
| 118 | +fn is_call_function(call_expr: &CallExpression, callee: &MemberExpression) -> bool { |
| 119 | + callee.static_property_name().is_some_and(|name| name == "call") |
| 120 | + && !call_expr.arguments.is_empty() |
| 121 | +} |
| 122 | + |
| 123 | +fn is_apply_function(call_expr: &CallExpression, callee: &MemberExpression) -> bool { |
| 124 | + callee.static_property_name().is_some_and(|name| name == "apply") |
| 125 | + && call_expr.arguments.len() == 2 |
| 126 | + && call_expr |
| 127 | + .arguments |
| 128 | + .get(1) |
| 129 | + .and_then(|arg| arg.as_expression()) |
| 130 | + .is_some_and(|expr| matches!(expr, Expression::ArrayExpression(_))) |
| 131 | +} |
| 132 | + |
| 133 | +fn is_call_or_non_variadic_apply(call_expr: &CallExpression, callee: &MemberExpression) -> bool { |
| 134 | + !callee.is_computed() |
| 135 | + && (is_call_function(call_expr, callee) || is_apply_function(call_expr, callee)) |
| 136 | +} |
| 137 | + |
| 138 | +fn as_member_expression_without_chain_expression<'a>( |
| 139 | + expr: &'a Expression, |
| 140 | +) -> Option<&'a MemberExpression<'a>> { |
| 141 | + match expr { |
| 142 | + Expression::ChainExpression(chain_expr) => { |
| 143 | + if let match_member_expression!(ChainElement) = chain_expr.expression { |
| 144 | + chain_expr.expression.as_member_expression() |
| 145 | + } else { |
| 146 | + None |
| 147 | + } |
| 148 | + } |
| 149 | + match_member_expression!(Expression) => expr.as_member_expression(), |
| 150 | + _ => None, |
| 151 | + } |
| 152 | +} |
| 153 | + |
| 154 | +#[test] |
| 155 | +fn test() { |
| 156 | + use crate::tester::Tester; |
| 157 | + |
| 158 | + let pass = vec![ |
| 159 | + "foo.apply(obj, 1, 2);", |
| 160 | + "obj.foo.apply(null, 1, 2);", |
| 161 | + "obj.foo.apply(otherObj, 1, 2);", |
| 162 | + "a.b(x, y).c.foo.apply(a.b(x, z).c, 1, 2);", |
| 163 | + "foo.apply(obj, [1, 2]);", |
| 164 | + "obj.foo.apply(null, [1, 2]);", |
| 165 | + "obj.foo.apply(otherObj, [1, 2]);", |
| 166 | + "a.b(x, y).c.foo.apply(a.b(x, z).c, [1, 2]);", |
| 167 | + "a.b.foo.apply(a.b.c, [1, 2]);", |
| 168 | + "foo.apply(null, args);", |
| 169 | + "obj.foo.apply(obj, args);", |
| 170 | + "var call; foo[call](null, 1, 2);", |
| 171 | + "var apply; foo[apply](null, [1, 2]);", |
| 172 | + "foo.call();", |
| 173 | + "obj.foo.call();", |
| 174 | + "foo.apply();", |
| 175 | + "obj.foo.apply();", |
| 176 | + "obj?.foo.bar.call(obj.foo, 1, 2);", // { "ecmaVersion": 2020 }, |
| 177 | + "class C { #call; wrap(foo) { foo.#call(undefined, 1, 2); } }", // { "ecmaVersion": 2022 } |
| 178 | + ]; |
| 179 | + |
| 180 | + let fail = vec![ |
| 181 | + "foo.call(undefined, 1, 2);", |
| 182 | + "foo.call(void 0, 1, 2);", |
| 183 | + "foo.call(null, 1, 2);", |
| 184 | + "obj.foo.call(obj, 1, 2);", |
| 185 | + "a.b.c.foo.call(a.b.c, 1, 2);", |
| 186 | + "a.b(x, y).c.foo.call(a.b(x, y).c, 1, 2);", |
| 187 | + "foo.apply(undefined, [1, 2]);", |
| 188 | + "foo.apply(void 0, [1, 2]);", |
| 189 | + "foo.apply(null, [1, 2]);", |
| 190 | + "obj.foo.apply(obj, [1, 2]);", |
| 191 | + "a.b.c.foo.apply(a.b.c, [1, 2]);", |
| 192 | + "a.b(x, y).c.foo.apply(a.b(x, y).c, [1, 2]);", |
| 193 | + "[].concat.apply([ ], [1, 2]);", |
| 194 | + "[].concat.apply([ |
| 195 | + /*empty*/ |
| 196 | + ], [1, 2]); |
| 197 | + ", |
| 198 | + r#"abc.get("foo", 0).concat.apply(abc . get("foo", 0 ), [1, 2]);"#, |
| 199 | + "foo.call?.(undefined, 1, 2);", // { "ecmaVersion": 2020 }, |
| 200 | + "foo?.call(undefined, 1, 2);", // { "ecmaVersion": 2020 }, |
| 201 | + "(foo?.call)(undefined, 1, 2);", // { "ecmaVersion": 2020 }, |
| 202 | + "obj.foo.call?.(obj, 1, 2);", // { "ecmaVersion": 2020 }, |
| 203 | + "obj?.foo.call(obj, 1, 2);", // { "ecmaVersion": 2020 }, |
| 204 | + "(obj?.foo).call(obj, 1, 2);", // { "ecmaVersion": 2020 }, |
| 205 | + "(obj?.foo.call)(obj, 1, 2);", // { "ecmaVersion": 2020 }, |
| 206 | + "obj?.foo.bar.call(obj?.foo, 1, 2);", // { "ecmaVersion": 2020 }, |
| 207 | + "(obj?.foo).bar.call(obj?.foo, 1, 2);", // { "ecmaVersion": 2020 }, |
| 208 | + "obj.foo?.bar.call(obj.foo, 1, 2);", // { "ecmaVersion": 2020 } |
| 209 | + ]; |
| 210 | + |
| 211 | + Tester::new(NoUselessCall::NAME, NoUselessCall::PLUGIN, pass, fail).test_and_snapshot(); |
| 212 | +} |
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