Merge pull request #161 from CodeshiftCommunity/putout

Adds remove-unused-vars via putout

Author: danieldelcore

.changeset/tidy-bobcats-lick.md

@@ -0,0 +1,5 @@
+---
+'@codeshift/mod-javascript': patch
+---
+
+Adds remove-unused-vars from putout as javascript preset

.gitignore

@@ -3,6 +3,7 @@
 plugin_packages/
 .vscode/
 .parcel-cache/
+package-lock.json
 
 # Generated website pages
 website/docs/registry-generated/*

community/javascript/package.json

@@ -17,10 +17,12 @@
   "devDependencies": {
     "@codeshift/cli": "^0.14.1",
     "@codeshift/test-utils": "^0.3.1",
+    "@putout/plugin-remove-unused-variables": "^5.1.0",
     "@types/jest": "^29.0.0",
     "@types/node": "^16.11.0",
     "jest": "^29.0.0",
     "prettier": "^2.0.0",
+    "putout": "^29.5.1",
     "ts-jest": "^29.0.0",
     "typescript": "^4.5.5"
   },

community/javascript/src/codeshift.config.js

@@ -8,5 +8,6 @@ module.exports = {
     'remove-debugger': require.resolve('./remove-debugger/transform'),
     'sort-object-props': require.resolve('./sort-object-props/transform'),
     'var-to-let': require.resolve('./var-to-let/transform'),
+    'remove-unused-vars': require.resolve('./remove-unused-vars/transform'),
   },
 };

community/javascript/src/remove-unused-vars/README.md

@@ -0,0 +1,18 @@
+# javascript#remove-unused-vars
+
+Codemods for javascript#remove-unused-vars
+
+Detects and removes unused variables in JavaScript code.
+
+_Credit:_ [https://github.com/coderaiser/putout/tree/master/packages/plugin-remove-unused-variables](https://github.com/coderaiser/putout/tree/master/packages/plugin-remove-unused-variables#readme)
+
+```js
+/* INPUT */
+const x = 1;
+const y = 2;
+console.log(y);
+
+/* OUTPUT */
+const y = 2;
+console.log(y);
+```

community/javascript/src/remove-unused-vars/transform.spec.ts

@@ -0,0 +1,151 @@
+import { applyTransform } from '@codeshift/test-utils';
+import * as transformer from './transform';
+
+describe('javascript#remove-unused-vars transform', () => {
+  it('should remove unused variables', async () => {
+    const result = await applyTransform(
+      transformer,
+      `
+const x = 1;
+const y = 2;
+console.log(y);
+    `,
+    );
+
+    expect(result).toMatchInlineSnapshot(`
+      "const y = 2;
+      console.log(y);"
+    `);
+  });
+
+  it('should not remove used variables', async () => {
+    const result = await applyTransform(
+      transformer,
+      `
+const x = 1;
+const y = 2;
+console.log(x + y);
+    `,
+    );
+    expect(result).toMatchInlineSnapshot(`
+      "const x = 1;
+      const y = 2;
+      console.log(x + y);"
+    `);
+  });
+
+  it('should remove unused variable in nested scope', async () => {
+    const result = await applyTransform(
+      transformer,
+      `
+{
+  if (true) {
+    const a = 1;
+  }
+}`,
+    );
+
+    expect(result).toMatchInlineSnapshot(`
+      "{
+        if (true) {}
+      }"
+    `);
+  });
+
+  it('should remove unused function in nested scope', async () => {
+    const result = await applyTransform(
+      transformer,
+      `
+function foo() {
+  if (true) {
+    const a = 1;
+  }
+}`,
+    );
+
+    expect(result).toMatchInlineSnapshot(`""`);
+  });
+
+  it('should remove unused variable in for loop', async () => {
+    const result = await applyTransform(
+      transformer,
+      `
+for (let i = 0; i < 10; i++) {
+  const a = i;
+}
+      `,
+    );
+
+    expect(result).toMatchInlineSnapshot(`"for (let i = 0; i < 10; i++) {}"`);
+  });
+
+  it('should remove unused variable in destructuring assignment', async () => {
+    const result = await applyTransform(
+      transformer,
+      `
+const { a, b } = { a: 1, b: 2 };
+console.log(a);
+      `,
+    );
+
+    expect(result).toMatchInlineSnapshot(`
+      "const {
+        a
+      } = { a: 1, b: 2 };
+      console.log(a);"
+    `);
+  });
+
+  it('should remove unused function argument', async () => {
+    const result = await applyTransform(
+      transformer,
+      `
+function foo(a, b) {
+  console.log(a);
+}
+foo(1);
+      `,
+    );
+
+    expect(result).toMatchInlineSnapshot(`
+      "function foo(a) {
+        console.log(a);
+      }
+      foo(1);"
+    `);
+  });
+
+  it('should not remove used variable in conditional', async () => {
+    const result = await applyTransform(
+      transformer,
+      `
+let a;
+if (true) {
+  a = 1;
+}
+console.log(a);
+      `,
+    );
+
+    expect(result).toMatchInlineSnapshot(`
+      "let a;
+      if (true) {
+        a = 1;
+      }
+      console.log(a);"
+    `);
+  });
+
+  it('should remove unused function declaration', async () => {
+    const result = await applyTransform(
+      transformer,
+      `
+function foo() {
+  console.log('Hello, world!');
+}
+      `,
+    );
+
+    expect(result).toMatchInlineSnapshot(`""`);
+  });
+});

community/javascript/src/remove-unused-vars/transform.ts

@@ -0,0 +1,13 @@
+import { FileInfo } from 'jscodeshift';
+// @ts-expect-error
+import putout from 'putout';
+// @ts-expect-error
+import removeUnusedVariables from '@putout/plugin-remove-unused-variables';
+
+export default function transformer(file: FileInfo) {
+  const output = putout(file.source, {
+    plugins: [['remove-unused-variables', removeUnusedVariables]],
+  });
+
+  return output.code;
+}