expose code location to MacroContext (#10171)

Author: snowystinger

CONTRIBUTING.md

@@ -16,7 +16,7 @@ Before starting make sure you have the following installed:
 
 - [git](https://git-scm.com)
 - [Node](https://nodejs.org) at LTS
-- [Yarn](https://yarnpkg.com) at v1
+- [Yarn](https://yarnpkg.com) at v4 and/or enable corepack
 - [Rust](https://www.rust-lang.org/tools/install) stable
 - [Flow](https://flow.org/en/docs/editors) IDE autocompletion and type-checking
 

packages/transformers/js/src/JSTransformer.js

@@ -165,6 +165,7 @@ type MacroAsset = {|
 // NOTE: Make sure this is in sync with the TypeScript definition in the @parcel/macros package.
 type MacroContext = {|
   addAsset(asset: MacroAsset): void,
+  loc: SourceLocation,
   invalidateOnFileChange(FilePath): void,
   invalidateOnFileCreate(FileCreateInvalidation): void,
   invalidateOnEnvChange(string): void,
@@ -544,6 +545,19 @@ export default (new Transformer({
                       specifierType: 'esm',
                     });
                   },
+                  loc: {
+                    filePath: asset.filePath,
+                    start: {
+                      line:
+                        loc.start_line + Number(asset.meta.startLine ?? 1) - 1,
+                      column: loc.start_col,
+                    },
+                    end: {
+                      line:
+                        loc.end_line + Number(asset.meta.startLine ?? 1) - 1,
+                      column: loc.end_col,
+                    },
+                  },
                   invalidateOnFileChange(filePath) {
                     asset.invalidateOnFileChange(filePath);
                   },

packages/utils/macros/macros.d.ts

@@ -1,6 +1,8 @@
 export interface MacroContext {
   /** Adds an asset as a dependency of the JS module that called this macro. */
   addAsset(asset: MacroAsset): void;
+  /** The source location of the macro call. */
+  loc: SourceLocation;
   /** Invalidate the macro call whenever the given file changes. */
   invalidateOnFileChange(filePath: string): void;
   /** Invalidate the macro call when a file matching the given pattern is created. */
@@ -13,6 +15,25 @@ export interface MacroContext {
   invalidateOnBuild(): void;
 }
 
+/**
+ * Source locations are 1-based, meaning lines and columns start at 1
+ */
+export type SourceLocation = {
+  readonly filePath: string;
+
+  /** inclusive */
+  readonly start: {
+    readonly line: number;
+    readonly column: number;
+  };
+
+  /** exclusive */
+  readonly end: {
+    readonly line: number;
+    readonly column: number;
+  };
+};
+
 export interface MacroAsset {
   /** The type of the asset (e.g. `'css'`). */
   type: string;