feat(unstable): add js lint plugin source code helpers

cli/js/40_lint.js

@@ -192,32 +192,103 @@ class Fixer {
   }
 }
 
+/**
+ * @implements {Deno.lint.SourceCode}
+ */
+export class SourceCode {
+  /** @type {string | null} */
+  #source = null;
+
+  /** @type {AstContext} */
+  #ctx;
+
+  /**
+   * @param {AstContext} ctx
+   */
+  constructor(ctx) {
+    this.#ctx = ctx;
+  }
+
+  get text() {
+    return this.#getSource();
+  }
+
+  get ast() {
+    const program = /** @type {*} */ (getNode(
+      this.#ctx,
+      this.#ctx.rootOffset,
+    ));
+
+    return program;
+  }
+
+  /**
+   * @param {Deno.lint.Node} [node]
+   * @returns {string}
+   */
+  getText(node) {
+    const source = this.#getSource();
+    if (node === undefined) {
+      return source;
+    }
+
+    return source.slice(node.range[0], node.range[1]);
+  }
+
+  /**
+   * @param {Deno.lint.Node} node
+   */
+  getAncestors(node) {
+    const { buf } = this.#ctx;
+
+    /** @type {Deno.lint.Node[]} */
+    const ancestors = [];
+
+    let parent = /** @type {*} */ (node)[INTERNAL_IDX];
+    while ((parent = readParent(buf, parent)) > AST_IDX_INVALID) {
+      if (readType(buf, parent) === AST_GROUP_TYPE) continue;
+
+      const parentNode = /** @type {*} */ (getNode(this.#ctx, parent));
+      if (parentNode !== null) {
+        ancestors.push(parentNode);
+      }
+    }
+
+    ancestors.reverse();
+
+    return ancestors;
+  }
+
+  /**
+   * @returns {string}
+   */
+  #getSource() {
+    if (this.#source === null) {
+      this.#source = op_lint_get_source();
+    }
+    return /** @type {string} */ (this.#source);
+  }
+}
+
 /**
  * Every rule gets their own instance of this class. This is the main
  * API lint rules interact with.
  * @implements {Deno.lint.RuleContext}
  */
 export class Context {
   id;
-
   fileName;
-
-  #source = null;
+  sourceCode;
 
   /**
+   * @param {AstContext} ctx
    * @param {string} id
    * @param {string} fileName
    */
-  constructor(id, fileName) {
+  constructor(ctx, id, fileName) {
     this.id = id;
     this.fileName = fileName;
-  }
-
-  source() {
-    if (this.#source === null) {
-      this.#source = op_lint_get_source();
-    }
-    return /** @type {*} */ (this.#source);
+    this.sourceCode = new SourceCode(ctx);
   }
 
   /**
@@ -961,8 +1032,8 @@ export function runPluginsForFile(fileName, serializedAst) {
         continue;
       }
 
-      const ctx = new Context(id, fileName);
-      const visitor = rule.create(ctx);
+      const ruleCtx = new Context(ctx, id, fileName);
+      const visitor = rule.create(ruleCtx);
 
       // deno-lint-ignore guard-for-in
       for (let key in visitor) {
@@ -1016,7 +1087,7 @@ export function runPluginsForFile(fileName, serializedAst) {
         const destroyFn = rule.destroy.bind(rule);
         destroyFns.push(() => {
           try {
-            destroyFn(ctx);
+            destroyFn(ruleCtx);
           } catch (err) {
             throw new Error(`Destroy hook of "${id}" errored`, { cause: err });
           }

cli/tools/lint/ast_buffer/swc.rs

@@ -94,6 +94,7 @@ use super::buffer::NodeRef;
 use super::ts_estree::AstNode;
 use super::ts_estree::MethodKind as TsEstreeMethodKind;
 use super::ts_estree::PropertyKind;
+use super::ts_estree::SourceKind;
 use super::ts_estree::TsEsTreeBuilder;
 use super::ts_estree::TsKeywordKind;
 use super::ts_estree::TsModuleKind;
@@ -120,7 +121,7 @@ pub fn serialize_swc_to_buffer(
         })
         .collect::<Vec<_>>();
 
-      ctx.write_program(&module.span, "module", children);
+      ctx.write_program(&module.span, SourceKind::Module, children);
     }
     Program::Script(script) => {
       let children = script
@@ -129,7 +130,7 @@ pub fn serialize_swc_to_buffer(
         .map(|stmt| serialize_stmt(&mut ctx, stmt))
         .collect::<Vec<_>>();
 
-      ctx.write_program(&script.span, "script", children);
+      ctx.write_program(&script.span, SourceKind::Script, children);
     }
   }
 

cli/tools/lint/ast_buffer/ts_estree.rs

@@ -499,12 +499,16 @@ impl TsEsTreeBuilder {
   pub fn write_program(
     &mut self,
     span: &Span,
-    source_kind: &str,
+    source_kind: SourceKind,
     body: Vec<NodeRef>,
   ) -> NodeRef {
     let id = self.ctx.append_node(AstNode::Program, span);
 
-    self.ctx.write_str(AstProp::SourceType, source_kind);
+    let kind = match source_kind {
+      SourceKind::Module => "module",
+      SourceKind::Script => "script",
+    };
+    self.ctx.write_str(AstProp::SourceType, kind);
     self.ctx.write_ref_vec(AstProp::Body, &id, body);
 
     self.ctx.set_root_idx(id.0);
@@ -2903,3 +2907,9 @@ pub enum MethodKind {
   Method,
   Set,
 }
+
+#[derive(Debug)]
+pub enum SourceKind {
+  Module,
+  Script,
+}

cli/tsc/dts/lib.deno.unstable.d.ts

@@ -1391,6 +1391,31 @@ declare namespace Deno {
       fix?(fixer: Fixer): FixData | Iterable<FixData>;
     }
 
+    /**
+     * @category Linter
+     * @experimental
+     */
+    export interface SourceCode {
+      /**
+       * Get the source test of a node. Omit `node` to get the
+       * full source code.
+       */
+      getText(node?: Node): string;
+      /**
+       * Returns array of ancestors of the current node, excluding the
+       * current node.
+       */
+      getAncestors(node: Node): Node[];
+      /**
+       * Get the full source code.
+       */
+      text: string;
+      /**
+       * Get the root node of the file. It's always the `Program` node.
+       */
+      ast: Program;
+    }
+
     /**
      * @category Linter
      * @experimental
@@ -1405,9 +1430,9 @@ declare namespace Deno {
        */
       fileName: string;
       /**
-       * Retrieve the source code of the current file.
+       * Helper methods for working with the raw source code.
        */
-      source(): string;
+      sourceCode: SourceCode;
       /**
        * Report a lint error.
        */
@@ -1497,6 +1522,17 @@ declare namespace Deno {
       source: string,
     ): Diagnostic[];
 
+    /**
+     * @category Linter
+     * @experimental
+     */
+    export interface Program {
+      type: "Program";
+      range: Range;
+      sourceType: "module" | "script";
+      body: Statement[];
+    }
+
     /**
      * @category Linter
      * @experimental
@@ -3857,6 +3893,7 @@ declare namespace Deno {
      * @experimental
      */
     export type Node =
+      | Program
       | Expression
       | Statement
       | TypeNode

tests/specs/lint/lint_plugin_source_code/__test__.jsonc

@@ -0,0 +1,9 @@
+{
+  "tempDir": true,
+  "steps": [
+    {
+      "args": "lint main.ts",
+      "output": "log.out"
+    }
+  ]
+}

tests/specs/lint/lint_plugin_source_code/deno.json

@@ -0,0 +1,5 @@
+{
+  "lint": {
+    "plugins": ["./plugin.ts"]
+  }
+}

tests/specs/lint/lint_plugin_source_code/log.out

@@ -0,0 +1,13 @@
+Source:
+const value = "unfixed";
+console.log(value);
+
+Source VariableDeclarator:
+value = "unfixed"
+
+Ancestors:
+[ "Program", "VariableDeclaration" ]
+
+Ast:
+Program
+Checked 1 file

tests/specs/lint/lint_plugin_source_code/main.ts

@@ -0,0 +1,2 @@
+const value = "unfixed";
+console.log(value);

tests/specs/lint/lint_plugin_source_code/plugin.ts

@@ -0,0 +1,28 @@
+export default {
+  name: "test-plugin",
+  rules: {
+    "my-rule": {
+      create(context) {
+        return {
+          VariableDeclarator(node) {
+            console.log(`Source:`);
+            console.log(context.sourceCode.getText());
+
+            console.log(`Source VariableDeclarator:`);
+            console.log(context.sourceCode.getText(node));
+            console.log();
+
+            console.log(`Ancestors:`);
+            console.log(
+              context.sourceCode.getAncestors(node).map((node) => node.type),
+            );
+            console.log();
+
+            console.log(`Ast:`);
+            console.log(context.sourceCode.ast.type);
+          },
+        };
+      },
+    },
+  },
+} satisfies Deno.lint.Plugin;