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fix(linter): add suggestion for jest/prefer-equality-matcher #20925

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Merged
camc314 merged 3 commits into from
Apr 1, 2026
+248 −9
Merged

fix(linter): add suggestion for jest/prefer-equality-matcher #20925

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57dcb7c
fix: add prefer-equality-matcher suggestions
eryue0220 Apr 1, 2026
fb57284
Merge branch 'main' into feat/jest-prefer-equality-matcher-suggestions
eryue0220 Apr 1, 2026
2a022ad
style tweaks
camc314 Apr 1, 2026
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257 changes: 248 additions & 9 deletions crates/oxc_linter/src/rules/jest/prefer_equality_matcher.rs
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Original file line number Diff line number Diff line change
@@ -1,6 +1,6 @@
use oxc_ast::{
AstKind,
ast::{Argument, Expression},
ast::{Argument, BinaryExpression, Expression},
};
use oxc_diagnostics::OxcDiagnostic;
use oxc_macros::declare_oxc_lint;
Expand All @@ -9,8 +9,12 @@ use oxc_syntax::operator::BinaryOperator;

use crate::{
context::LintContext,
fixer::RuleFixer,
rule::Rule,
utils::{PossibleJestNode, parse_expect_jest_fn_call},
utils::{
KnownMemberExpressionProperty, PossibleJestNode, is_equality_matcher,
parse_expect_jest_fn_call,
},
};

fn use_equality_matcher_diagnostic(span: Span) -> OxcDiagnostic {
Expand Down Expand Up @@ -65,7 +69,7 @@ declare_oxc_lint!(
PreferEqualityMatcher,
jest,
style,
pending,
suggestion
);

impl Rule for PreferEqualityMatcher {
Expand All @@ -81,10 +85,11 @@ impl Rule for PreferEqualityMatcher {
impl PreferEqualityMatcher {
pub fn run<'a>(possible_jest_node: &PossibleJestNode<'a, '_>, ctx: &LintContext<'a>) {
let node = possible_jest_node.node;
let AstKind::CallExpression(call_expr) = node.kind() else {
let AstKind::CallExpression(matcher_call_expr) = node.kind() else {
return;
};
let Some(jest_fn_call) = parse_expect_jest_fn_call(call_expr, possible_jest_node, ctx)
let Some(jest_fn_call) =
parse_expect_jest_fn_call(matcher_call_expr, possible_jest_node, ctx)
else {
return;
};
Expand All @@ -93,10 +98,10 @@ impl PreferEqualityMatcher {
return;
};
let expr = expect_parent.get_inner_expression();
let Expression::CallExpression(call_expr) = expr else {
let Expression::CallExpression(expect_call_expr) = expr else {
return;
};
let Some(argument) = call_expr.arguments.first() else {
let Some(argument) = expect_call_expr.arguments.first() else {
return;
};

Expand All @@ -114,13 +119,91 @@ impl PreferEqualityMatcher {
return;
};

ctx.diagnostic(use_equality_matcher_diagnostic(matcher.span));
if !is_equality_matcher(matcher) {
return;
}
let Some(first_matcher_arg) = jest_fn_call.args.first().and_then(Argument::as_expression)
else {
return;
};
let Expression::BooleanLiteral(matcher_arg_value) =
first_matcher_arg.get_inner_expression()
else {
return;
};

let modifiers = jest_fn_call.modifiers();
let has_not_modifier = modifiers.iter().any(|modifier| modifier.is_name_equal("not"));
let add_not_modifier = (if binary_expr.operator == BinaryOperator::StrictInequality {
!matcher_arg_value.value
} else {
matcher_arg_value.value
}) == has_not_modifier;

let fixer = RuleFixer::new(FixKind::Suggestion, ctx);
let suggestions = ["toBe", "toEqual", "toStrictEqual"].into_iter().map(|eq_matcher| {
// Preserve trailing commas: expect(a === b,).toBe(true,) -> expect(a,).toBe(b,)
let call_span_end =
fixer.source_range(Span::new(binary_expr.span.end, expect_call_expr.span.end));
let arg_span_end = fixer
.source_range(Span::new(matcher_arg_value.span.end, matcher_call_expr.span.end));
let content = Self::build_code(
binary_expr,
call_span_end,
arg_span_end,
&jest_fn_call.local,
&modifiers,
eq_matcher,
add_not_modifier,
fixer,
);
fixer
.replace(matcher_call_expr.span, content)
.with_message(format!("Use `{eq_matcher}`"))
});

ctx.diagnostic_with_suggestions(use_equality_matcher_diagnostic(matcher.span), suggestions);
}

fn build_code<'a>(
binary_expr: &BinaryExpression<'a>,
call_span_end: &str,
arg_span_end: &str,
local_name: &str,
modifiers: &[&KnownMemberExpressionProperty<'a>],
equality_matcher: &str,
add_not_modifier: bool,
fixer: RuleFixer<'_, 'a>,
) -> String {
let mut content = fixer.codegen();
content.print_str(local_name);
content.print_ascii_byte(b'(');
content.print_expression(&binary_expr.left);
content.print_str(call_span_end);
content.print_ascii_byte(b'.');
for modifier in modifiers {
let Some(modifier_name) = modifier.name() else {
continue;
};
if modifier_name != "not" {
content.print_str(&modifier_name);
content.print_ascii_byte(b'.');
}
}
if add_not_modifier {
content.print_str("not.");
}
content.print_str(equality_matcher);
content.print_ascii_byte(b'(');
content.print_expression(&binary_expr.right);
content.print_str(arg_span_end);
content.into_source_text()
}
}

#[test]
fn test() {
use crate::tester::Tester;
use crate::tester::{ExpectFixTestCase, Tester};

let mut pass = vec![
("expect.hasAssertions", None),
Expand Down Expand Up @@ -182,10 +265,166 @@ fn test() {
("expect(a !== b).resolves.not.toBe(false);", None),
];

let fix: Vec<ExpectFixTestCase> = vec![
(
"expect(a === b).toBe(true);",
("expect(a).toBe(b);", "expect(a).toEqual(b);", "expect(a).toStrictEqual(b);"),
)
.into(),
(
"expect(a === b,).toBe(true,);",
("expect(a,).toBe(b,);", "expect(a,).toEqual(b,);", "expect(a,).toStrictEqual(b,);"),
)
.into(),
(
"expect(a === b).toBe(false);",
(
"expect(a).not.toBe(b);",
"expect(a).not.toEqual(b);",
"expect(a).not.toStrictEqual(b);",
),
)
.into(),
(
"expect(a === b).resolves.toBe(true);",
(
"expect(a).resolves.toBe(b);",
"expect(a).resolves.toEqual(b);",
"expect(a).resolves.toStrictEqual(b);",
),
)
.into(),
(
"expect(a === b).resolves.toBe(false);",
(
"expect(a).resolves.not.toBe(b);",
"expect(a).resolves.not.toEqual(b);",
"expect(a).resolves.not.toStrictEqual(b);",
),
)
.into(),
(
"expect(a === b).not.toBe(true);",
(
"expect(a).not.toBe(b);",
"expect(a).not.toEqual(b);",
"expect(a).not.toStrictEqual(b);",
),
)
.into(),
(
"expect(a === b).not.toBe(false);",
("expect(a).toBe(b);", "expect(a).toEqual(b);", "expect(a).toStrictEqual(b);"),
)
.into(),
(
"expect(a === b).resolves.not.toBe(true);",
(
"expect(a).resolves.not.toBe(b);",
"expect(a).resolves.not.toEqual(b);",
"expect(a).resolves.not.toStrictEqual(b);",
),
)
.into(),
(
"expect(a === b).resolves.not.toBe(false);",
(
"expect(a).resolves.toBe(b);",
"expect(a).resolves.toEqual(b);",
"expect(a).resolves.toStrictEqual(b);",
),
)
.into(),
(
r#"expect(a === b)["resolves"].not.toBe(false);"#,
(
"expect(a).resolves.toBe(b);",
"expect(a).resolves.toEqual(b);",
"expect(a).resolves.toStrictEqual(b);",
),
)
.into(),
(
r#"expect(a === b)["resolves"]["not"]["toBe"](false);"#,
(
"expect(a).resolves.toBe(b);",
"expect(a).resolves.toEqual(b);",
"expect(a).resolves.toStrictEqual(b);",
),
)
.into(),
(
"expect(a !== b).toBe(true);",
(
"expect(a).not.toBe(b);",
"expect(a).not.toEqual(b);",
"expect(a).not.toStrictEqual(b);",
),
)
.into(),
(
"expect(a !== b).toBe(false);",
("expect(a).toBe(b);", "expect(a).toEqual(b);", "expect(a).toStrictEqual(b);"),
)
.into(),
(
"expect(a !== b).resolves.toBe(true);",
(
"expect(a).resolves.not.toBe(b);",
"expect(a).resolves.not.toEqual(b);",
"expect(a).resolves.not.toStrictEqual(b);",
),
)
.into(),
(
"expect(a !== b).resolves.toBe(false);",
(
"expect(a).resolves.toBe(b);",
"expect(a).resolves.toEqual(b);",
"expect(a).resolves.toStrictEqual(b);",
),
)
.into(),
(
"expect(a !== b).not.toBe(true);",
("expect(a).toBe(b);", "expect(a).toEqual(b);", "expect(a).toStrictEqual(b);"),
)
.into(),
(
"expect(a !== b).not.toBe(false);",
(
"expect(a).not.toBe(b);",
"expect(a).not.toEqual(b);",
"expect(a).not.toStrictEqual(b);",
),
)
.into(),
(
"expect(a !== b).resolves.not.toBe(true);",
(
"expect(a).resolves.toBe(b);",
"expect(a).resolves.toEqual(b);",
"expect(a).resolves.toStrictEqual(b);",
),
)
.into(),
(
"expect(a !== b).resolves.not.toBe(false);",
(
"expect(a).resolves.not.toBe(b);",
"expect(a).resolves.not.toEqual(b);",
"expect(a).resolves.not.toStrictEqual(b);",
),
)
.into(),
];

pass.extend(pass_vitest);
fail.extend(fail_vitest);

Tester::new(PreferEqualityMatcher::NAME, PreferEqualityMatcher::PLUGIN, pass, fail)
.with_jest_plugin(true)
.with_vitest_plugin(true)
.expect_fix(fix)
.test_and_snapshot();
}
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