feat(linter/eslint-plugin-vitest): implement prefer-to-be-falsy (#4770)

Related to https://github.com/oxc-project/oxc/issues/4656

crates/oxc_linter/src/rules.rs

@@ -449,6 +449,7 @@ mod promise {
 
 mod vitest {
     pub mod no_import_node_test;
+    pub mod prefer_to_be_falsy;
     pub mod prefer_to_be_truthy;
 }
 
@@ -855,5 +856,6 @@ oxc_macros::declare_all_lint_rules! {
     promise::no_new_statics,
     promise::param_names,
     vitest::no_import_node_test,
+    vitest::prefer_to_be_falsy,
     vitest::prefer_to_be_truthy,
 }

crates/oxc_linter/src/rules/vitest/prefer_to_be_falsy.rs

@@ -0,0 +1,97 @@
+use oxc_macros::declare_oxc_lint;
+
+use crate::{
+    context::LintContext,
+    rule::Rule,
+    utils::{collect_possible_jest_call_node, prefer_to_be_simply_bool},
+};
+
+#[derive(Debug, Default, Clone)]
+pub struct PreferToBeFalsy;
+
+declare_oxc_lint!(
+    /// ### What it does
+    ///
+    /// This rule warns when `toBe(false)` is used with `expect` or `expectTypeOf`. With `--fix`, it will be replaced with `toBeFalsy()`.
+    ///
+    /// ### Examples
+    ///
+    /// ```javascript
+    /// // bad
+    /// expect(foo).toBe(false)
+    /// expectTypeOf(foo).toBe(false)
+    ///
+    /// // good
+    /// expect(foo).toBeFalsy()
+    /// expectTypeOf(foo).toBeFalsy()
+    /// ```
+    PreferToBeFalsy,
+    style,
+    fix
+);
+
+impl Rule for PreferToBeFalsy {
+    fn run_once(&self, ctx: &LintContext) {
+        for possible_vitest_node in &collect_possible_jest_call_node(ctx) {
+            prefer_to_be_simply_bool(possible_vitest_node, ctx, false);
+        }
+    }
+}
+
+#[test]
+fn test() {
+    use crate::tester::Tester;
+
+    let pass = vec![
+        "[].push(false)",
+        r#"expect("something");"#,
+        "expect(true).toBeTrue();",
+        "expect(false).toBeTrue();",
+        "expect(false).toBeFalsy();",
+        "expect(true).toBeFalsy();",
+        "expect(value).toEqual();",
+        "expect(value).not.toBeFalsy();",
+        "expect(value).not.toEqual();",
+        "expect(value).toBe(undefined);",
+        "expect(value).not.toBe(undefined);",
+        "expect(false).toBe(true)",
+        "expect(value).toBe();",
+        "expect(true).toMatchSnapshot();",
+        r#"expect("a string").toMatchSnapshot(false);"#,
+        r#"expect("a string").not.toMatchSnapshot();"#,
+        "expect(something).toEqual('a string');",
+        "expect(false).toBe",
+        "expectTypeOf(false).toBe",
+    ];
+
+    let fail = vec![
+        "expect(true).toBe(false);",
+        "expect(wasSuccessful).toEqual(false);",
+        "expect(fs.existsSync('/path/to/file')).toStrictEqual(false);",
+        r#"expect("a string").not.toBe(false);"#,
+        r#"expect("a string").not.toEqual(false);"#,
+        r#"expectTypeOf("a string").not.toEqual(false);"#,
+    ];
+
+    let fix = vec![
+        ("expect(true).toBe(false);", "expect(true).toBeFalsy();", None),
+        ("expect(wasSuccessful).toEqual(false);", "expect(wasSuccessful).toBeFalsy();", None),
+        (
+            "expect(fs.existsSync('/path/to/file')).toStrictEqual(false);",
+            "expect(fs.existsSync('/path/to/file')).toBeFalsy();",
+            None,
+        ),
+        (r#"expect("a string").not.toBe(false);"#, r#"expect("a string").not.toBeFalsy();"#, None),
+        (
+            r#"expect("a string").not.toEqual(false);"#,
+            r#"expect("a string").not.toBeFalsy();"#,
+            None,
+        ),
+        (
+            r#"expectTypeOf("a string").not.toEqual(false);"#,
+            r#"expectTypeOf("a string").not.toBeFalsy();"#,
+            None,
+        ),
+    ];
+    Tester::new(PreferToBeFalsy::NAME, pass, fail).expect_fix(fix).test_and_snapshot();
+}

crates/oxc_linter/src/rules/vitest/prefer_to_be_truthy.rs

@@ -1,24 +1,11 @@
-use oxc_ast::{
-    ast::{Argument, Expression},
-    AstKind,
-};
-use oxc_diagnostics::OxcDiagnostic;
 use oxc_macros::declare_oxc_lint;
-use oxc_span::Span;
 
 use crate::{
     context::LintContext,
     rule::Rule,
-    utils::{
-        collect_possible_jest_call_node, is_equality_matcher,
-        parse_expect_and_typeof_vitest_fn_call, PossibleJestNode,
-    },
+    utils::{collect_possible_jest_call_node, prefer_to_be_simply_bool},
 };
 
-fn use_to_be_truthy(span0: Span) -> OxcDiagnostic {
-    OxcDiagnostic::warn("Use `toBeTruthy` instead.").with_label(span0)
-}
-
 #[derive(Debug, Default, Clone)]
 pub struct PreferToBeTruthy;
 
@@ -46,55 +33,7 @@ declare_oxc_lint!(
 impl Rule for PreferToBeTruthy {
     fn run_once(&self, ctx: &LintContext) {
         for possible_vitest_node in &collect_possible_jest_call_node(ctx) {
-            Self::run(possible_vitest_node, ctx);
-        }
-    }
-}
-
-impl PreferToBeTruthy {
-    fn run<'a>(possible_vitest_node: &PossibleJestNode<'a, '_>, ctx: &LintContext<'a>) {
-        let node = possible_vitest_node.node;
-        let AstKind::CallExpression(call_expr) = node.kind() else {
-            return;
-        };
-        let Some(vitest_expect_fn_call) =
-            parse_expect_and_typeof_vitest_fn_call(call_expr, possible_vitest_node, ctx)
-        else {
-            return;
-        };
-        let Some(matcher) = vitest_expect_fn_call.matcher() else {
-            return;
-        };
-
-        if !is_equality_matcher(matcher) || vitest_expect_fn_call.args.len() == 0 {
-            return;
-        }
-
-        let Some(arg_expr) = vitest_expect_fn_call.args.first().and_then(Argument::as_expression)
-        else {
-            return;
-        };
-
-        if let Expression::BooleanLiteral(arg) = arg_expr.get_inner_expression() {
-            if arg.value {
-                let span = Span::new(matcher.span.start, call_expr.span.end);
-
-                let is_cmp_mem_expr = match matcher.parent {
-                    Some(Expression::ComputedMemberExpression(_)) => true,
-                    Some(
-                        Expression::StaticMemberExpression(_)
-                        | Expression::PrivateFieldExpression(_),
-                    ) => false,
-                    _ => return,
-                };
-
-                ctx.diagnostic_with_fix(use_to_be_truthy(span), |fixer| {
-                    let new_matcher =
-                        if is_cmp_mem_expr { "[\"toBeTruthy\"]()" } else { "toBeTruthy()" };
-
-                    fixer.replace(span, new_matcher)
-                });
-            }
+            prefer_to_be_simply_bool(possible_vitest_node, ctx, true);
         }
     }
 }

crates/oxc_linter/src/snapshots/prefer_to_be_falsy.snap

@@ -0,0 +1,44 @@
+---
+source: crates/oxc_linter/src/tester.rs
+---
+  ⚠ eslint-plugin-vitest(prefer-to-be-falsy): Use `toBeFalsy` instead.
+   ╭─[prefer_to_be_falsy.tsx:1:14]
+ 1 │ expect(true).toBe(false);
+   ·              ───────────
+   ╰────
+  help: Replace `toBe(false)` with `toBeFalsy()`.
+
+  ⚠ eslint-plugin-vitest(prefer-to-be-falsy): Use `toBeFalsy` instead.
+   ╭─[prefer_to_be_falsy.tsx:1:23]
+ 1 │ expect(wasSuccessful).toEqual(false);
+   ·                       ──────────────
+   ╰────
+  help: Replace `toEqual(false)` with `toBeFalsy()`.
+
+  ⚠ eslint-plugin-vitest(prefer-to-be-falsy): Use `toBeFalsy` instead.
+   ╭─[prefer_to_be_falsy.tsx:1:40]
+ 1 │ expect(fs.existsSync('/path/to/file')).toStrictEqual(false);
+   ·                                        ────────────────────
+   ╰────
+  help: Replace `toStrictEqual(false)` with `toBeFalsy()`.
+
+  ⚠ eslint-plugin-vitest(prefer-to-be-falsy): Use `toBeFalsy` instead.
+   ╭─[prefer_to_be_falsy.tsx:1:24]
+ 1 │ expect("a string").not.toBe(false);
+   ·                        ───────────
+   ╰────
+  help: Replace `toBe(false)` with `toBeFalsy()`.
+
+  ⚠ eslint-plugin-vitest(prefer-to-be-falsy): Use `toBeFalsy` instead.
+   ╭─[prefer_to_be_falsy.tsx:1:24]
+ 1 │ expect("a string").not.toEqual(false);
+   ·                        ──────────────
+   ╰────
+  help: Replace `toEqual(false)` with `toBeFalsy()`.
+
+  ⚠ eslint-plugin-vitest(prefer-to-be-falsy): Use `toBeFalsy` instead.
+   ╭─[prefer_to_be_falsy.tsx:1:30]
+ 1 │ expectTypeOf("a string").not.toEqual(false);
+   ·                              ──────────────
+   ╰────
+  help: Replace `toEqual(false)` with `toBeFalsy()`.

crates/oxc_linter/src/utils/vitest.rs

@@ -1,7 +1,15 @@
 use crate::LintContext;
-use oxc_ast::ast::CallExpression;
+use oxc_ast::{
+    ast::{Argument, CallExpression, Expression},
+    AstKind,
+};
+use oxc_diagnostics::OxcDiagnostic;
+use oxc_span::Span;
 
-use super::{parse_jest_fn_call, ParsedExpectFnCall, ParsedJestFnCallNew, PossibleJestNode};
+use super::{
+    is_equality_matcher, parse_jest_fn_call, ParsedExpectFnCall, ParsedJestFnCallNew,
+    PossibleJestNode,
+};
 
 pub fn parse_expect_and_typeof_vitest_fn_call<'a>(
     call_expr: &'a CallExpression<'a>,
@@ -16,3 +24,57 @@ pub fn parse_expect_and_typeof_vitest_fn_call<'a>(
         ParsedJestFnCallNew::GeneralJest(_) => None,
     }
 }
+
+pub fn prefer_to_be_simply_bool<'a>(
+    possible_vitest_node: &PossibleJestNode<'a, '_>,
+    ctx: &LintContext<'a>,
+    value: bool,
+) {
+    let node = possible_vitest_node.node;
+    let AstKind::CallExpression(call_expr) = node.kind() else {
+        return;
+    };
+    let Some(vitest_expect_fn_call) =
+        parse_expect_and_typeof_vitest_fn_call(call_expr, possible_vitest_node, ctx)
+    else {
+        return;
+    };
+    let Some(matcher) = vitest_expect_fn_call.matcher() else {
+        return;
+    };
+    if !is_equality_matcher(matcher) || vitest_expect_fn_call.args.len() == 0 {
+        return;
+    }
+    let Some(arg_expr) = vitest_expect_fn_call.args.first().and_then(Argument::as_expression)
+    else {
+        return;
+    };
+
+    if let Expression::BooleanLiteral(arg) = arg_expr.get_inner_expression() {
+        if arg.value == value {
+            let span = Span::new(matcher.span.start, call_expr.span.end);
+
+            let is_cmp_mem_expr = match matcher.parent {
+                Some(Expression::ComputedMemberExpression(_)) => true,
+                Some(
+                    Expression::StaticMemberExpression(_) | Expression::PrivateFieldExpression(_),
+                ) => false,
+                _ => return,
+            };
+
+            let call_name = if value { "toBeTruthy" } else { "toBeFalsy" };
+
+            ctx.diagnostic_with_fix(
+                OxcDiagnostic::warn(format!("Use `{call_name}` instead.")).with_label(span),
+                |fixer| {
+                    let new_matcher = if is_cmp_mem_expr {
+                        format!("[\"{call_name}\"]()")
+                    } else {
+                        format!("{call_name}()")
+                    };
+                    fixer.replace(span, new_matcher)
+                },
+            );
+        }
+    }
+}