feat(biome_js_analyze): implement noExcessiveLinesPerFunction

Author: mehm8128

.changeset/mighty-regions-begin.md

@@ -0,0 +1,25 @@
+---
+"@biomejs/biome": minor
+---
+
+Added the rule [noExcessiveLinesPerFunction](https://biomejs.dev/linter/rules/no-excessive-lines-per-function/).
+This rule restrict a maximum number of lines of code in a function.
+
+The following code is now reported as invalid when the limit of maximum lines is set to 4:
+
+```js
+function foo() {
+  const x = 0;
+  const y = 1;
+  const z = 2;
+}
+```
+
+The following code is now reported as valid when the limit of maximum lines is set to 4:
+
+```jsx
+const bar = () => {
+  const x = 0;
+  const z = 2;
+};
+```

crates/biome_cli/src/execute/migrate/eslint_any_rule_to_biome.rs

@@ -154,6 +154,7 @@ define_categories! {
     "lint/nursery/noDestructuredProps": "https://biomejs.dev/linter/rules/no-destructured-props",
     "lint/nursery/noDoneCallback": "https://biomejs.dev/linter/rules/no-done-callback",
     "lint/nursery/noDuplicateAtImportRules": "https://biomejs.dev/linter/rules/no-duplicate-at-import-rules",
+    "lint/nursery/noExcessiveLinesPerFunction": "https://biomejs.dev/linter/rules/no-excessive-lines-per-function",
     "lint/nursery/noFloatingPromises": "https://biomejs.dev/linter/rules/no-floating-promises",
     "lint/nursery/noGlobalDirnameFilename": "https://biomejs.dev/linter/rules/no-global-dirname-filename",
     "lint/nursery/noImportCycles": "https://biomejs.dev/linter/rules/no-import-cycles",

crates/biome_configuration/src/analyzer/linter/rules.rs

@@ -7,6 +7,7 @@ pub mod no_await_in_loop;
 pub mod no_bitwise_operators;
 pub mod no_constant_binary_expression;
 pub mod no_destructured_props;
+pub mod no_excessive_lines_per_function;
 pub mod no_floating_promises;
 pub mod no_global_dirname_filename;
 pub mod no_import_cycles;
@@ -39,4 +40,4 @@ pub mod use_single_js_doc_asterisk;
 pub mod use_sorted_classes;
 pub mod use_symbol_description;
 pub mod use_unique_element_ids;
-declare_lint_group! { pub Nursery { name : "nursery" , rules : [self :: no_await_in_loop :: NoAwaitInLoop , self :: no_bitwise_operators :: NoBitwiseOperators , self :: no_constant_binary_expression :: NoConstantBinaryExpression , self :: no_destructured_props :: NoDestructuredProps , self :: no_floating_promises :: NoFloatingPromises , self :: no_global_dirname_filename :: NoGlobalDirnameFilename , self :: no_import_cycles :: NoImportCycles , self :: no_nested_component_definitions :: NoNestedComponentDefinitions , self :: no_noninteractive_element_interactions :: NoNoninteractiveElementInteractions , self :: no_process_global :: NoProcessGlobal , self :: no_restricted_elements :: NoRestrictedElements , self :: no_secrets :: NoSecrets , self :: no_shadow :: NoShadow , self :: no_ts_ignore :: NoTsIgnore , self :: no_unresolved_imports :: NoUnresolvedImports , self :: no_unwanted_polyfillio :: NoUnwantedPolyfillio , self :: no_useless_backref_in_regex :: NoUselessBackrefInRegex , self :: no_useless_escape_in_string :: NoUselessEscapeInString , self :: no_useless_undefined :: NoUselessUndefined , self :: use_adjacent_getter_setter :: UseAdjacentGetterSetter , self :: use_consistent_object_definition :: UseConsistentObjectDefinition , self :: use_consistent_response :: UseConsistentResponse , self :: use_exhaustive_switch_cases :: UseExhaustiveSwitchCases , self :: use_explicit_type :: UseExplicitType , self :: use_exports_last :: UseExportsLast , self :: use_for_component :: UseForComponent , self :: use_google_font_preconnect :: UseGoogleFontPreconnect , self :: use_index_of :: UseIndexOf , self :: use_iterable_callback_return :: UseIterableCallbackReturn , self :: use_numeric_separators :: UseNumericSeparators , self :: use_object_spread :: UseObjectSpread , self :: use_parse_int_radix :: UseParseIntRadix , self :: use_single_js_doc_asterisk :: UseSingleJsDocAsterisk , self :: use_sorted_classes :: UseSortedClasses , self :: use_symbol_description :: UseSymbolDescription , self :: use_unique_element_ids :: UseUniqueElementIds ,] } }
+declare_lint_group! { pub Nursery { name : "nursery" , rules : [self :: no_await_in_loop :: NoAwaitInLoop , self :: no_bitwise_operators :: NoBitwiseOperators , self :: no_constant_binary_expression :: NoConstantBinaryExpression , self :: no_destructured_props :: NoDestructuredProps , self :: no_excessive_lines_per_function :: NoExcessiveLinesPerFunction , self :: no_floating_promises :: NoFloatingPromises , self :: no_global_dirname_filename :: NoGlobalDirnameFilename , self :: no_import_cycles :: NoImportCycles , self :: no_nested_component_definitions :: NoNestedComponentDefinitions , self :: no_noninteractive_element_interactions :: NoNoninteractiveElementInteractions , self :: no_process_global :: NoProcessGlobal , self :: no_restricted_elements :: NoRestrictedElements , self :: no_secrets :: NoSecrets , self :: no_shadow :: NoShadow , self :: no_ts_ignore :: NoTsIgnore , self :: no_unresolved_imports :: NoUnresolvedImports , self :: no_unwanted_polyfillio :: NoUnwantedPolyfillio , self :: no_useless_backref_in_regex :: NoUselessBackrefInRegex , self :: no_useless_escape_in_string :: NoUselessEscapeInString , self :: no_useless_undefined :: NoUselessUndefined , self :: use_adjacent_getter_setter :: UseAdjacentGetterSetter , self :: use_consistent_object_definition :: UseConsistentObjectDefinition , self :: use_consistent_response :: UseConsistentResponse , self :: use_exhaustive_switch_cases :: UseExhaustiveSwitchCases , self :: use_explicit_type :: UseExplicitType , self :: use_exports_last :: UseExportsLast , self :: use_for_component :: UseForComponent , self :: use_google_font_preconnect :: UseGoogleFontPreconnect , self :: use_index_of :: UseIndexOf , self :: use_iterable_callback_return :: UseIterableCallbackReturn , self :: use_numeric_separators :: UseNumericSeparators , self :: use_object_spread :: UseObjectSpread , self :: use_parse_int_radix :: UseParseIntRadix , self :: use_single_js_doc_asterisk :: UseSingleJsDocAsterisk , self :: use_sorted_classes :: UseSortedClasses , self :: use_symbol_description :: UseSymbolDescription , self :: use_unique_element_ids :: UseUniqueElementIds ,] } }

crates/biome_diagnostics_categories/src/categories.rs

@@ -0,0 +1,198 @@
+use crate::services::semantic::Semantic;
+use ::serde::{Deserialize, Serialize};
+use biome_analyze::{
+    Rule, RuleDiagnostic, RuleSource, RuleSourceKind, context::RuleContext, declare_lint_rule,
+};
+use biome_console::markup;
+use biome_deserialize_macros::Deserializable;
+use biome_js_syntax::{
+    AnyFunctionLike, AnyJsFunction, JsCallExpression, JsParenthesizedExpression,
+};
+use biome_rowan::AstNode;
+#[cfg(feature = "schemars")]
+use schemars::JsonSchema;
+use std::num::NonZeroU8;
+
+declare_lint_rule! {
+    /// Restrict a maximum number of lines of code in a function.
+    ///
+    /// Some people consider large functions a code smell. Large functions tend to do a lot of things and can make it hard following what’s going on. Many coding style guides dictate a limit of the number of lines that a function can comprise of. This rule can help enforce that style.
+    ///
+    /// ## Options
+    ///
+    /// The rule supports the following options:
+    ///
+    /// ```json,options
+    /// {
+    ///     "options": {
+    ///        "max": 4,
+    ///        "skipBlankLines": true,
+    ///        "iifes": true
+    ///     }
+    /// }
+    /// ```
+    ///
+    /// - `max` (positive integer, default: 50): The maximum number of lines allowed in a function.
+    /// - `skip_blank_lines` (bool, default: false): A boolean value which indicates whether blank lines are counted or not.
+    /// - `iifes` (bool, default: false): A boolean value which indicates whether IIFEs (Immediately Invoked Function Expression) are checked or not.
+    ///
+    /// ## Examples
+    ///
+    /// ### Invalid
+    ///
+    /// ```js,expect_diagnostic,use_options
+    /// function foo () {
+    ///   const x = 0;
+    ///   const y = 1;
+    ///   const z = 2;
+    /// };
+    /// ```
+    ///
+    /// ```js,expect_diagnostic,use_options
+    /// const bar = () => {
+    ///   const x = 0;
+    ///
+    ///   const y = 1;
+    ///   const z = 2;
+    /// };
+    /// ```
+    ///
+    /// ```js,expect_diagnostic,use_options
+    /// class Baz {
+    ///	  foo() {
+    ///     const x = 0;
+    ///	    const y = 0;
+    ///     const z = 2;
+    ///	  };
+    /// };
+    /// ```
+    ///
+    /// ```js,expect_diagnostic,use_options
+    /// (() => {
+    ///	 const x = 0;
+    ///	 const y = 0;
+    ///	 const z = 0;
+    /// })();
+    /// ```
+    ///
+    /// ### Valid
+    ///
+    /// ```js,use_options
+    ///  function foo () {
+    ///     const x = 0;
+    ///     const y = 1;
+    /// };
+    ///
+    /// const bar = () => {
+    ///   const x = 0;
+    ///
+    ///   const y = 1;
+    /// };
+    ///
+    /// class Baz {
+    ///	  foo() {
+    ///     const x = 0;
+    ///	    const y = 0;
+    ///	  };
+    /// };
+    ///
+    /// (() => {
+    ///	 const x = 0;
+    ///	 const y = 0;
+    /// })();
+    /// ```
+    ///
+    pub NoExcessiveLinesPerFunction {
+        version: "2.0.0",
+        name: "noExcessiveLinesPerFunction",
+        language: "js",
+        recommended: false,
+        sources: &[RuleSource::Eslint("max-lines-per-function")],
+        source_kind: RuleSourceKind::SameLogic,
+    }
+}
+
+impl Rule for NoExcessiveLinesPerFunction {
+    type Query = Semantic<AnyFunctionLike>;
+    type State = State;
+    type Signals = Option<Self::State>;
+    type Options = NoExcessiveLinesPerFunctionOptions;
+
+    fn run(ctx: &RuleContext<Self>) -> Self::Signals {
+        let binding = ctx.query();
+        let options = ctx.options();
+
+        if let AnyFunctionLike::AnyJsFunction(func) = binding {
+            if is_iife(func) && !options.iifes {
+                return None;
+            }
+        };
+
+        let func_string = binding.to_string();
+        let func_lines = func_string.trim().lines();
+
+        let function_line_count = if options.skip_blank_lines {
+            func_lines
+                .filter(|line| !line.trim().is_empty())
+                .collect::<Vec<_>>()
+                .len()
+        } else {
+            func_lines.collect::<Vec<_>>().len()
+        };
+
+        if function_line_count <= options.max.get().into() {
+            return None;
+        }
+
+        Some(State {
+            function_line_count,
+        })
+    }
+
+    fn diagnostic(ctx: &RuleContext<Self>, state: &Self::State) -> Option<RuleDiagnostic> {
+        let node = ctx.query();
+        let options = ctx.options();
+
+        Some(
+            RuleDiagnostic::new(
+                rule_category!(),
+                node.range(),
+                markup! {
+                    "This function has too many lines ("{state.function_line_count}"). Maximum allowed is "{options.max.to_string()}"."
+                },
+            )
+            .note(markup! {
+                "Consider refactoring this function to split it into smaller functions."
+            }),
+        )
+    }
+}
+
+fn is_iife(func: &AnyJsFunction) -> bool {
+    func.parent::<JsParenthesizedExpression>()
+        .and_then(|expr| expr.parent::<JsCallExpression>())
+        .is_some()
+}
+
+pub struct State {
+    function_line_count: usize,
+}
+
+#[derive(Clone, Debug, Deserialize, Deserializable, Eq, PartialEq, Serialize)]
+#[cfg_attr(feature = "schema", derive(JsonSchema))]
+#[serde(rename_all = "camelCase", deny_unknown_fields, default)]
+pub struct NoExcessiveLinesPerFunctionOptions {
+    pub max: NonZeroU8,
+    pub skip_blank_lines: bool,
+    pub iifes: bool,
+}
+
+impl Default for NoExcessiveLinesPerFunctionOptions {
+    fn default() -> Self {
+        Self {
+            max: NonZeroU8::new(50).unwrap(),
+            skip_blank_lines: false,
+            iifes: false,
+        }
+    }
+}

crates/biome_js_analyze/src/lint/nursery.rs

@@ -0,0 +1,41 @@
+const foo = () => {
+	const x = 2;
+	const y = 1;
+	return x + y;
+};
+
+function bar() {
+	const x = 2;
+	const y = 1;
+	return x + y;
+}
+
+function name() {
+	var x = 5;
+
+	var x = 2;
+}
+
+function foo(
+	aaa = 1,
+	bbb = 2,
+	ccc = 3
+) {
+	return aaa + bbb + ccc
+}
+
+function parent() {
+	var x = 0;
+	function nested() {
+		var y = 0;
+		x = 2;
+	}
+};
+
+class foo {
+	method() {
+		let y = 10;
+		let x = 20;
+		return y + x;
+	}
+}