feat(linter) eslint-plugin-unicorn: prefer blob reading methods (#1168)

crates/oxc_linter/src/rules.rs

@@ -153,6 +153,7 @@ mod unicorn {
     pub mod no_thenable;
     pub mod no_unnecessary_await;
     pub mod prefer_array_flat_map;
+    pub mod prefer_blob_reading_methods;
     pub mod prefer_code_point;
     pub mod prefer_date_now;
     pub mod prefer_logical_operator_over_ternary;
@@ -284,6 +285,7 @@ oxc_macros::declare_all_lint_rules! {
     unicorn::no_thenable,
     unicorn::no_unnecessary_await,
     unicorn::prefer_array_flat_map,
+    unicorn::prefer_blob_reading_methods,
     unicorn::prefer_code_point,
     unicorn::prefer_date_now,
     unicorn::prefer_logical_operator_over_ternary,

crates/oxc_linter/src/rules/unicorn/prefer_blob_reading_methods.rs

@@ -0,0 +1,90 @@
+use oxc_ast::{ast::Expression, AstKind};
+use oxc_diagnostics::{
+    miette::{self, Diagnostic},
+    thiserror::{self, Error},
+};
+use oxc_macros::declare_oxc_lint;
+use oxc_span::Span;
+
+use crate::{context::LintContext, rule::Rule, AstNode};
+
+#[derive(Debug, Error, Diagnostic)]
+#[error("eslint-plugin-unicorn(prefer-blob-reading-methods): Prefer `Blob#{1}()` over `FileReader#{2}(blob)`.")]
+#[diagnostic(severity(warning))]
+struct PreferBlobReadingMethodsDiagnostic(#[label] pub Span, pub &'static str, pub &'static str);
+
+#[derive(Debug, Default, Clone)]
+pub struct PreferBlobReadingMethods;
+
+declare_oxc_lint!(
+    /// ### What it does
+    ///
+    /// Recommends using `Blob#text()` and `Blob#arrayBuffer()` over `FileReader#readAsText()` and `FileReader#readAsArrayBuffer()`.
+    ///
+    /// ### Why is this bad?
+    ///
+    /// `FileReader` predates promises, and the newer [`Blob#arrayBuffer()`](https://developer.mozilla.org/en-US/docs/Web/API/Blob/arrayBuffer) and [`Blob#text()`](https://developer.mozilla.org/en-US/docs/Web/API/Blob/text) methods are much cleaner and easier to use.
+    ///
+    /// ### Example
+    /// ```javascript
+    /// // bad
+    /// const arrayBuffer = await new Promise((resolve, reject) => {
+    /// 	const fileReader = new FileReader();
+    /// 	fileReader.addEventListener('load', () => {
+    /// 		resolve(fileReader.result);
+    /// 	});
+    /// 	fileReader.addEventListener('error', () => {
+    /// 		reject(fileReader.error);
+    /// 	});
+    /// 	fileReader.readAsArrayBuffer(blob);
+    /// });
+    ///
+    /// // good
+    /// const arrayBuffer = await blob.arrayBuffer();
+    /// ```
+    PreferBlobReadingMethods,
+    pedantic
+);
+
+impl Rule for PreferBlobReadingMethods {
+    fn run<'a>(&self, node: &AstNode<'a>, ctx: &LintContext<'a>) {
+        let AstKind::CallExpression(call_expr) = node.kind() else { return };
+
+        let Expression::MemberExpression(member_expr) = &call_expr.callee else { return };
+
+        if member_expr.is_computed()
+            || member_expr.optional()
+            || call_expr.optional
+            || call_expr.arguments.len() != 1
+        {
+            return;
+        }
+
+        let (current, replacement, span) = match member_expr.static_property_info() {
+            Some((span, "readAsText")) => ("readAsText", "text", span),
+            Some((span, "readAsArrayBuffer")) => ("readAsArrayBuffer", "arrayBuffer", span),
+            _ => return,
+        };
+
+        ctx.diagnostic(PreferBlobReadingMethodsDiagnostic(span, replacement, current));
+    }
+}
+
+#[test]
+fn test() {
+    use crate::tester::Tester;
+
+    let pass = vec![
+        r#"blob.arrayBuffer()"#,
+        r#"blob.text()"#,
+        r#"new Response(blob).arrayBuffer()"#,
+        r#"new Response(blob).text()"#,
+        r#"fileReader.readAsDataURL(blob)"#,
+        r#"fileReader.readAsBinaryString(blob)"#,
+        r#"fileReader.readAsText(blob, "ascii")"#,
+    ];
+
+    let fail = vec![r#"fileReader.readAsArrayBuffer(blob)"#, r#"fileReader.readAsText(blob)"#];
+
+    Tester::new_without_config(PreferBlobReadingMethods::NAME, pass, fail).test_and_snapshot();
+}

crates/oxc_linter/src/snapshots/prefer_blob_reading_methods.snap

@@ -0,0 +1,17 @@
+---
+source: crates/oxc_linter/src/tester.rs
+expression: prefer_blob_reading_methods
+---
+  ⚠ eslint-plugin-unicorn(prefer-blob-reading-methods): Prefer `Blob#arrayBuffer()` over `FileReader#readAsArrayBuffer(blob)`.
+   ╭─[prefer_blob_reading_methods.tsx:1:1]
+ 1 │ fileReader.readAsArrayBuffer(blob)
+   ·            ─────────────────
+   ╰────
+
+  ⚠ eslint-plugin-unicorn(prefer-blob-reading-methods): Prefer `Blob#text()` over `FileReader#readAsText(blob)`.
+   ╭─[prefer_blob_reading_methods.tsx:1:1]
+ 1 │ fileReader.readAsText(blob)
+   ·            ──────────
+   ╰────
+
+