feat(core): Add config option to skip files considered for imports (#140

)

* Add option to skip src files with pattern

* improve skip option explanation

Co-authored-by: Nadeesha Cabral <[email protected]>

* Improve explanation of skip opt in readme

* Refactor getPotentiallyUnused

* Add an integration test for skip pattern

* Fix integration test for skip pattern

Co-authored-by: Nadeesha Cabral <[email protected]>

.gitignore

@@ -10,4 +10,4 @@ Thumbs.db
 *.log
 package-lock.json
 .eslintcache
-./integration/testproject/outfile # this will be generated by integration tests
+integration/testproject/outfile # this will be generated by integration tests

README.md

@@ -45,6 +45,7 @@ ts-prune supports CLI and file configuration via [cosmiconfig](https://github.co
 - `-p, --project` - __tsconfig.json__ path(`tsconfig.json` by default)
 - `-i, --ignore` - errors ignore RegExp pattern
 - `-e, --error` - return error code if unused exports are found
+- `-s, --skip` - skip these files when determining whether code is used. (For example, `*.test.ts?` will stop ts-prune from considering an export in test file usages)
 
 CLI configuration options:
 ```bash 

integration/outfile.base

@@ -12,4 +12,5 @@ src/internal-uses.ts:13 - Row (used in module)
 src/internal-uses.ts:17 - UnusedProps
 src/dynamic/fail.ts:1 - foo
 src/dynamic/fail.ts:3 - bar
+src/skipPattern/foo.ts:1 - foo
 src/wildcard/foo.ts:5 - vUnused

integration/test.sh

@@ -17,7 +17,7 @@ step "Linking ts-prune from step 1"
 npm link ts-prune
 
 step "Run ts-prune"
-ts-prune | tee outfile
+ts-prune --skip ".test.ts" | tee outfile
 
 step "Diff between outputs"
 DIFF=$(diff outfile ../outfile.base)
@@ -48,7 +48,7 @@ fi
 
 step "Cleanup"
 rm ../../package-lock.json # remnants of the npm link
-rm ./integration/testproject/outfile # generated outfile
+rm outfile # generated outfile
 
 echo "🏁"
 exit $EXIT_CODE

integration/testproject/src/skipPattern/foo.test.ts

@@ -0,0 +1,7 @@
+import { foo } from "./foo";
+
+describe("foo", () => {
+  it("should return false", () => {
+    expect(foo()).toBeFalsy;
+  })
+})

integration/testproject/src/skipPattern/foo.ts

@@ -0,0 +1 @@
+export const foo = () => false;

src/analyzer.test.ts

@@ -34,11 +34,27 @@ export function UseFoo(foo: string) {
 }
 `;
 
+const barSrc = `
+export const bar = () => false;
+`;
+
+const testBarSrc = `
+import { bar } from './bar';
+
+describe("bar", () => {
+  it("should return false", () => {
+    expect(bar()).toBe.toBeFalsy;
+  });
+});
+`;
+
 describe("analyzer", () => {
   const project = new Project();
   const foo = project.createSourceFile("/project/foo.ts", fooSrc);
   const useFoo = project.createSourceFile("/project/use-foo.ts", useFooSrc);
   const star = project.createSourceFile("/project/star.ts", starImportSrc);
+  const bar = project.createSourceFile("/project/bar.ts", barSrc);
+  const testBar = project.createSourceFile("/project/bar.test.ts", testBarSrc);
 
   it("should track import wildcards", () => {
     // TODO(danvk): rename this to importSideEffects()
@@ -70,6 +86,26 @@ describe("analyzer", () => {
     });
   });
 
+  it("should not skip source files without a pattern", () => {
+    // while bar.test.ts is included, bar is used
+    expect(getPotentiallyUnused(bar)).toEqual({
+      file: "/project/bar.ts",
+      symbols: [],
+      type: 0,
+    });
+  });
+
+  it("should skip source files matching a pattern", () => {
+    // when bar.test.ts is exclude by the skip pattern, bar is unused
+    expect(getPotentiallyUnused(bar, ".test.ts")).toEqual({
+      file: "/project/bar.ts",
+      symbols: [
+        { line: 2, name: "bar", usedInModule: false },
+      ],
+      type: 0,
+    });
+  });
+
   it("should track usage through star imports", () => {
     const importNode = star.getFirstDescendantByKindOrThrow(
       ts.SyntaxKind.ImportDeclaration

src/analyzer.ts

@@ -17,6 +17,7 @@ import { getNodesOfKind } from './util/getNodesOfKind';
 import countBy from "lodash/fp/countBy";
 import last from "lodash/fp/last";
 import { realpathSync } from "fs";
+import { IConfigInterface } from "./configurator";
 
 type OnResultType = (result: IAnalysedResult) => void;
 
@@ -191,26 +192,39 @@ const getDefinitelyUsed = (file: SourceFile): IAnalysedResult[] => ([
   ...exportWildCards(file),
 ]);
 
-export const getPotentiallyUnused = (file: SourceFile): IAnalysedResult => {
+const getReferences = (
+  originalList: SourceFileReferencingNodes[],
+  skipPattern?: string
+): SourceFileReferencingNodes[] =>  {
+  if(skipPattern){
+    const regExp = new RegExp(skipPattern);
+    return originalList.filter(file =>
+      !regExp.test(file.getSourceFile().compilerNode.fileName)
+    );
+  }
+  return originalList;
+}
+export const getPotentiallyUnused = (file: SourceFile, skipPattern?: string): IAnalysedResult => {
   const exported = getExported(file);
 
   const idsInFile = file.getDescendantsOfKind(ts.SyntaxKind.Identifier);
   const referenceCounts = countBy(x => x)((idsInFile || []).map(node => node.getText()));
   const referencedInFile = Object.entries(referenceCounts)
     .reduce(
-      (previous, [name, count]) => previous.concat(count > 1 ? [name] : []), 
+      (previous, [name, count]) => previous.concat(count > 1 ? [name] : []),
       []
     );
 
-  const referenced = file
-    .getReferencingNodesInOtherSourceFiles()
-    .reduce(
+  const referenced = getReferences(
+    file.getReferencingNodesInOtherSourceFiles(),
+    skipPattern
+  ).reduce(
       (previous, node: SourceFileReferencingNodes) => {
         const kind = node.getKind().toString();
         const value = nodeHandlers?.[kind]?.(node) ?? [];
-        
+
         return previous.concat(value);
-      }, 
+      },
       []
     );
 
@@ -232,10 +246,10 @@ const emitTsConfigEntrypoints = (entrypoints: string[], onResult: OnResultType)
     type: AnalysisResultTypeEnum.DEFINITELY_USED,
   })).forEach(emittable => onResult(emittable))
 
-export const analyze = (project: Project, onResult: OnResultType, entrypoints: string[]) => {
+export const analyze = (project: Project, onResult: OnResultType, entrypoints: string[], skipPattern?: string) => {
   project.getSourceFiles().forEach(file => {
     [
-      getPotentiallyUnused(file),
+      getPotentiallyUnused(file, skipPattern),
       ...getDefinitelyUsed(file),
     ].forEach(result => {
       if (!result.file) return // Prevent passing along a "null" filepath. Fixes #105

src/configurator.ts

@@ -6,12 +6,14 @@ export interface IConfigInterface {
   project?: string;
   ignore?: string;
   error?: string;
+  skip?: string;
 }
 
 const defaultConfig: IConfigInterface = {
   project: "tsconfig.json",
   ignore: undefined,
   error: undefined,
+  skip: undefined,
 }
 
 const onlyKnownConfigOptions = pick(Object.keys(defaultConfig));
@@ -23,6 +25,7 @@ export const getConfig = () => {
     .option('-p, --project [project]', 'TS project configuration file (tsconfig.json)', 'tsconfig.json')
     .option('-i, --ignore [regexp]', 'Path ignore RegExp pattern')
     .option('-e, --error', 'Return error code if unused exports are found')
+    .option('-s, --skip [regexp]', 'skip these files when determining whether code is used')
     .parse(process.argv))
 
   const defaultConfig = {
@@ -40,4 +43,4 @@ export const getConfig = () => {
   };
 
   return config;
-}
+}

src/runner.ts

@@ -17,7 +17,7 @@ export const run = (config: IConfigInterface, output = console.log) => {
 
   const state = new State();
 
-  analyze(project, state.onResult, entrypoints);
+  analyze(project, state.onResult, entrypoints, config.skip);
 
   const presented = present(state);