diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 3b6824b..73d4f07 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -32,3 +32,23 @@ jobs:
       run: pnpm install
     - name: run tests
       run: SHELL=/bin/bash pnpm test
+
+  typecheck:
+    name: Type Check
+    runs-on: ubuntu-latest
+
+    steps:
+    - name: Checkout Commit
+      uses: actions/checkout@v1
+    - name: Setup Node
+      uses: actions/setup-node@v1
+      with:
+        node-version: '20'
+    - name: install pnpm
+      run: |
+        npm install pnpm -g
+        pnpm --version
+    - name: pnpm install
+      run: pnpm install
+    - name: type check
+      run: pnpm run typecheck
diff --git a/.gitignore b/.gitignore
index 71876ed..c8394bb 100644
--- a/.gitignore
+++ b/.gitignore
@@ -10,3 +10,4 @@ quick-test.js
 coverage/
 tabtab/
 test/tabtab.log
+/types
diff --git a/lib/filename.js b/lib/filename.js
index 91d18cc..7bfeaca 100644
--- a/lib/filename.js
+++ b/lib/filename.js
@@ -5,7 +5,7 @@ const { COMPLETION_FILE_EXT } = require('./constants');
  * @param {String} shell
  * @returns {String}
  */
-const templateFileName = (shell = systemShell()) => {
+const templateFileName = shell => {
   const ext = COMPLETION_FILE_EXT[shell];
   if (!ext) {
     throw new Error(`Unsupported shell: ${shell}`);
@@ -19,7 +19,7 @@ const templateFileName = (shell = systemShell()) => {
  * @param {String} shell
  * @returns {String}
  */
-const completionFileName = (name, shell = systemShell()) => {
+const completionFileName = (name, shell) => {
   const ext = COMPLETION_FILE_EXT[shell];
   if (!ext) {
     throw new Error(`Unsupported shell: ${shell}`);
@@ -32,7 +32,7 @@ const completionFileName = (name, shell = systemShell()) => {
  * @param {String} shell
  * @returns {String}
  */
-const tabtabFileName = (shell = systemShell()) => {
+const tabtabFileName = shell => {
   const ext = COMPLETION_FILE_EXT[shell];
   if (!ext) {
     throw new Error(`Unsupported shell: ${shell}`);
diff --git a/lib/index.js b/lib/index.js
index d351ce3..03b8f84 100644
--- a/lib/index.js
+++ b/lib/index.js
@@ -13,7 +13,7 @@ const debug = tabtabDebug('tabtab');
  * @param {String} options.name - The package configured for completion
  * @param {String} options.completer - The program the will act as the completer for the `name` program
  * @param {String} options.shell
- * @returns {String}
+ * @returns {Promise.<String>}
  */
 const getCompletionScript = async ({ name, completer, shell }) => {
   if (!name) throw new TypeError('options.name is required');
@@ -29,10 +29,12 @@ const getCompletionScript = async ({ name, completer, shell }) => {
  * - SHELL (bash, zsh or fish)
  * - Path to shell script (with sensible defaults)
  *
- * @param {Object} Options to use with namely `name` and `completer`
- *
+ * @param {Object} options to use with namely `name` and `completer`
+ * @param {String} options.name
+ * @param {String} options.completer
+ * @param {String} options.shell
  */
-const install = async (options = { name: '', completer: '' }) => {
+const install = async (options) => {
   const { name, completer } = options;
   if (!name) throw new TypeError('options.name is required');
   if (!completer) throw new TypeError('options.completer is required');
@@ -142,21 +144,23 @@ const parseEnv = env => {
   };
 };
 
+/**
+ * @typedef {Object} CompletionItem
+ * @property {String} name
+ * @property {String} [description]
+ */
+
 /**
  * Helper to normalize String and Objects with { name, description } when logging out.
  *
- * @param {String|Object} item - Item to normalize
+ * @param {String|CompletionItem} item - Item to normalize
+ * @param {String} shell
+ * @returns {CompletionItem} normalized items
  */
-const completionItem = item => {
+const completionItem = (item, shell) => {
   debug('completion item', item);
 
-  if (item.name || item.description) {
-    return {
-      name: item.name,
-      description: item.description || ''
-    };
-  }
-  const shell = systemShell();
+  if (typeof item === 'object') return item
 
   let name = item;
   let description = '';
@@ -175,12 +179,6 @@ const completionItem = item => {
   };
 };
 
-/**
- * @typedef {Object} CompletionItem
- * @property {String} name
- * @property {String} description
- */
-
 /**
  * Main logging utility to pass completion items.
  *
@@ -190,7 +188,7 @@ const completionItem = item => {
  * Bash needs in addition to filter out the args for the completion to work
  * (zsh, fish don't need this).
  *
- * @param {Array.<CompletionItem>} args to log, Strings or Objects with name and
+ * @param {Array.<CompletionItem | String>} args to log, Strings or Objects with name and
  * description property.
  * @param {String} shell
  */
@@ -200,12 +198,12 @@ const log = (args, shell = systemShell()) => {
   }
 
   // Normalize arguments if there are some Objects { name, description } in them.
-  args = args.map(completionItem).map(item => {
+  let lines = args.map(item => completionItem(item, shell)).map(item => {
     const { name: rawName, description: rawDescription } = item;
 
-    const name = shell === 'zsh' ? rawName.replace(/:/g, '\\:') : rawName;
+    const name = shell === 'zsh' ? rawName?.replace(/:/g, '\\:') : rawName;
     const description =
-      shell === 'zsh' ? rawDescription.replace(/:/g, '\\:') : rawDescription;
+      shell === 'zsh' ? rawDescription?.replace(/:/g, '\\:') : rawDescription;
     let str = name;
 
     if (shell === 'zsh' && description) {
@@ -219,11 +217,11 @@ const log = (args, shell = systemShell()) => {
 
   if (shell === 'bash') {
     const env = parseEnv(process.env);
-    args = args.filter(arg => arg.indexOf(env.last) === 0);
+    lines = lines.filter(arg => arg.indexOf(env.last) === 0);
   }
 
-  for (const arg of args) {
-    console.log(`${arg}`);
+  for (const line of lines) {
+    console.log(`${line}`);
   }
 };
 
diff --git a/lib/installer.js b/lib/installer.js
index bc3cc38..8131109 100644
--- a/lib/installer.js
+++ b/lib/installer.js
@@ -109,11 +109,12 @@ const checkFilenameForLine = async (filename, line) => {
     filecontent = await readFile(untildify(filename), 'utf8');
   } catch (err) {
     if (err.code !== 'ENOENT') {
-      return console.error(
+      console.error(
         'Got an error while trying to read from %s file',
         filename,
         err
       );
+      return false;
     }
   }
 
diff --git a/lib/prompt.js b/lib/prompt.js
index 1a729ff..06a9063 100644
--- a/lib/prompt.js
+++ b/lib/prompt.js
@@ -22,6 +22,7 @@ const prompt = async () => {
 
   const finalAnswers = {};
 
+  // @ts-ignore
   const { shell } = await enquirer.prompt(questions);
   debug('answers', shell);
 
@@ -30,6 +31,7 @@ const prompt = async () => {
 
   Object.assign(finalAnswers, { location, shell });
 
+  // @ts-ignore
   const { locationOK } = await enquirer.prompt({
     type: 'confirm',
     name: 'locationOK',
@@ -42,6 +44,7 @@ const prompt = async () => {
   }
 
   // otherwise, ask for specific **absolute** path
+  // @ts-ignore
   const { userLocation } = await enquirer.prompt({
     name: 'userLocation',
     message: 'Which path then ? Must be absolute.',
diff --git a/lib/tsconfig.json b/lib/tsconfig.json
new file mode 100644
index 0000000..a361ac7
--- /dev/null
+++ b/lib/tsconfig.json
@@ -0,0 +1,8 @@
+{
+  "extends": "../tsconfig.common.json",
+  "compilerOptions": {
+    "declaration": true,
+    "emitDeclarationOnly": true,
+    "declarationDir": "../types",
+  }
+}
diff --git a/package.json b/package.json
index af17ed8..ebcc749 100644
--- a/package.json
+++ b/package.json
@@ -3,11 +3,15 @@
   "name": "@pnpm/tabtab",
   "description": "tab completion helpers, for node cli programs. Inspired by npm completion.",
   "main": "lib/index.js",
+  "types": "types/index.d.ts",
   "engines": {
     "node": ">=18"
   },
   "scripts": {
     "test": "mkdir -p ~/.config/tabtab && DEBUG='tabtab*' c8 mocha --timeout 5000",
+    "typecheck": "pnpm run build && tsc -p test --noEmit",
+    "build": "tsc -p lib",
+    "prepublishOnly": "pnpm run build",
     "posttest": "npm run eslint",
     "mocha": "DEBUG='tabtab*' mocha --timeout 5000",
     "coverage": "c8 report --reporter=text-lcov | coveralls",
@@ -34,7 +38,10 @@
     "npm-watch": "^0.4.0",
     "remark-cli": "^5.0.0",
     "remark-toc": "^5.1.1",
-    "serve": "^10.1.2"
+    "serve": "^10.1.2",
+    "typescript": "^5.3.3",
+    "@types/mocha": "^7.0.0",
+    "@types/node": "^20.11.13"
   },
   "license": "MIT",
   "keywords": [
diff --git a/pnpm-lock.yaml b/pnpm-lock.yaml
index 5451919..ecce81e 100644
--- a/pnpm-lock.yaml
+++ b/pnpm-lock.yaml
@@ -24,6 +24,12 @@ dependencies:
     version: 4.0.0(patch_hash=wtr47rwd2khewhm6li7h5z3egq)
 
 devDependencies:
+  '@types/mocha':
+    specifier: ^7.0.0
+    version: 7.0.2
+  '@types/node':
+    specifier: ^20.11.13
+    version: 20.11.13
   auto-changelog:
     specifier: ^1.16.4
     version: 1.16.4
@@ -60,6 +66,9 @@ devDependencies:
   serve:
     specifier: ^10.1.2
     version: 10.1.2
+  typescript:
+    specifier: ^5.3.3
+    version: 5.3.3
 
 packages:
 
@@ -107,11 +116,15 @@ packages:
   /@types/keyv@3.1.4:
     resolution: {integrity: sha512-BQ5aZNSCpj7D6K2ksrRCTmKRLEpnPvWDiLPfoGyhZ++8YtiK9d/3DBKPJgry359X/P1PfruyYwvnvwFjuEiEIg==}
     dependencies:
-      '@types/node': 20.11.10
+      '@types/node': 20.11.13
     dev: true
 
-  /@types/node@20.11.10:
-    resolution: {integrity: sha512-rZEfe/hJSGYmdfX9tvcPMYeYPW2sNl50nsw4jZmRcaG0HIAb0WYEpsB05GOb53vjqpyE9GUhlDQ4jLSoB5q9kg==}
+  /@types/mocha@7.0.2:
+    resolution: {integrity: sha512-ZvO2tAcjmMi8V/5Z3JsyofMe3hasRcaw88cto5etSVMwVQfeivGAlEYmaQgceUSVYFofVjT+ioHsATjdWcFt1w==}
+    dev: true
+
+  /@types/node@20.11.13:
+    resolution: {integrity: sha512-5G4zQwdiQBSWYTDAH1ctw2eidqdhMJaNsiIDKHFr55ihz5Trl2qqR8fdrT732yPBho5gkNxXm67OxWFBqX9aPg==}
     dependencies:
       undici-types: 5.26.5
     dev: true
@@ -119,7 +132,7 @@ packages:
   /@types/responselike@1.0.3:
     resolution: {integrity: sha512-H/+L+UkTV33uf49PH5pCAUBVPNj2nDBXTN+qS1dOwyyg24l3CcicicCA7ca+HMvJBZcFgl5r8e+RR6elsb4Lyw==}
     dependencies:
-      '@types/node': 20.11.10
+      '@types/node': 20.11.13
     dev: true
 
   /@types/unist@2.0.10:
@@ -5007,6 +5020,12 @@ packages:
     resolution: {integrity: sha512-/aCDEGatGvZ2BIk+HmLf4ifCJFwvKFNb9/JeZPMulfgFracn9QFcAf5GO8B/mweUjSoblS5In0cWhqpfs/5PQA==}
     dev: true
 
+  /typescript@5.3.3:
+    resolution: {integrity: sha512-pXWcraxM0uxAS+tN0AG/BF2TyqmHO014Z070UsJ+pFvYuRSq8KH8DmWpnbXe0pEPDHXZV3FcAbJkijJ5oNEnWw==}
+    engines: {node: '>=14.17'}
+    hasBin: true
+    dev: true
+
   /typical@2.6.1:
     resolution: {integrity: sha512-ofhi8kjIje6npGozTip9Fr8iecmYfEbS06i0JnIg+rh51KakryWF4+jX8lLKZVhy6N+ID45WYSFCxPOdTWCzNg==}
     dev: true
diff --git a/test/fixtures/tabtab-install.js b/test/fixtures/tabtab-install.js
index 3cf4f33..c898336 100644
--- a/test/fixtures/tabtab-install.js
+++ b/test/fixtures/tabtab-install.js
@@ -3,6 +3,7 @@ const tabtab = require('../..');
 (async () => {
   await tabtab.install({
     name: 'foo',
-    completer: 'foo-complete'
+    completer: 'foo-complete',
+    shell: 'bash',
   });
 })();
diff --git a/test/installer.js b/test/installer.js
index 333d0d9..1766e71 100644
--- a/test/installer.js
+++ b/test/installer.js
@@ -9,7 +9,8 @@ const {
   writeToShellConfig,
   writeToCompletionScript
 } = require('../lib/installer');
-const { COMPLETION_DIR, TABTAB_SCRIPT_NAME } = require('../lib/constants');
+const { COMPLETION_DIR } = require('../lib/constants');
+const { tabtabFileName } = require('../lib/filename');
 const { rejects, setupSuiteForInstall } = require('./utils');
 
 // For node 7 / 8
@@ -63,7 +64,7 @@ describe('installer', () => {
       const bashDir = untildify(path.join(COMPLETION_DIR, 'bash'));
       await mkdir(bashDir, { recursive: true });
       // Make sure __tabtab.bash starts with empty content, it'll be restored by setupSuiteForInstall
-      await writeFile(path.join(bashDir, `${TABTAB_SCRIPT_NAME}.bash`), '');
+      await writeFile(path.join(bashDir, tabtabFileName('bash')), '');
     });
 
     it('installs the necessary line into ~/.bashrc', () =>
diff --git a/test/log.js b/test/log.js
index 4fbeec0..532698a 100644
--- a/test/log.js
+++ b/test/log.js
@@ -4,6 +4,7 @@ const tabtab = require('..');
 describe('tabtab.log', () => {
   it('tabtab.log throws an Error in case args is not an Array', () => {
     assert.throws(() => {
+      // @ts-ignore
       tabtab.log('foo', 'bar');
     }, /^Error: log: Invalid arguments, must be an array$/);
   });
diff --git a/test/tabtab-install.js b/test/tabtab-install.js
index 5c93935..2a9aa41 100644
--- a/test/tabtab-install.js
+++ b/test/tabtab-install.js
@@ -6,7 +6,8 @@ const path = require('path');
 const fs = require('fs');
 const { promisify } = require('util');
 const tabtab = require('..');
-const { COMPLETION_DIR, TABTAB_SCRIPT_NAME } = require('../lib/constants');
+const { COMPLETION_DIR } = require('../lib/constants');
+const { tabtabFileName } = require('../lib/filename');
 const { rejects, setupSuiteForInstall } = require('./utils');
 
 const readFile = promisify(fs.readFile);
@@ -26,11 +27,13 @@ describe('tabtab.install()', () => {
   });
 
   it('rejects on missing options', async () => {
+    // @ts-ignore
     await assert.rejects(async () => tabtab.install(), TypeError);
   });
 
   it('rejects on missing name options', async () => {
     await assert.rejects(
+      // @ts-ignore
       async () => tabtab.install({}),
       /options\.name is required/
     );
@@ -38,6 +41,7 @@ describe('tabtab.install()', () => {
 
   it('rejects on missing completer options', async () => {
     await assert.rejects(
+      // @ts-ignore
       async () => tabtab.install({ name: 'foo' }),
       /options\.completer is required/
     );
@@ -55,7 +59,7 @@ describe('tabtab.install()', () => {
     const bashDir = untildify(path.join(COMPLETION_DIR, 'bash'));
     await mkdir(bashDir, { recursive: true });
     // Make sure __tabtab.bash starts with empty content, it'll be restored by setupSuiteForInstall
-    await writeFile(path.join(bashDir, `${TABTAB_SCRIPT_NAME}.bash`), '');
+    await writeFile(path.join(bashDir, tabtabFileName('bash')), '');
 
     await tabtab.install({ name: 'foo', completer: 'foo', shell: 'bash' });
 
diff --git a/test/tsconfig.json b/test/tsconfig.json
new file mode 100644
index 0000000..22b7188
--- /dev/null
+++ b/test/tsconfig.json
@@ -0,0 +1,6 @@
+{
+  "extends": "../tsconfig.common.json",
+  "compilerOptions": {
+    "noEmit": true,
+  }
+}
diff --git a/test/utils/index.js b/test/utils/index.js
index fe9149c..f9f5603 100644
--- a/test/utils/index.js
+++ b/test/utils/index.js
@@ -2,7 +2,8 @@ const fs = require('fs');
 const path = require('path');
 const untildify = require('untildify');
 const { promisify } = require('util');
-const { COMPLETION_DIR, TABTAB_SCRIPT_NAME } = require('../../lib/constants');
+const { COMPLETION_DIR } = require('../../lib/constants');
+const { tabtabFileName } = require('../../lib/filename');
 
 const { exists } = require('../../lib/utils');
 
@@ -12,7 +13,7 @@ const readFile = promisify(fs.readFile);
 /**
  * Returns both { exists, content }
  *
- * @param {filename} filename - The file to check and read
+ * @param {String} filename - The file to check and read
  */
 const readIfExists = async filename => {
   /* eslint-disable no-return-await */
@@ -29,7 +30,7 @@ const readIfExists = async filename => {
 const afterWrites = (prevBashrc, prevScript) => async () => {
   const bashrc = untildify('~/.bashrc');
   const tabtabScript = untildify(
-    path.join(COMPLETION_DIR, `${TABTAB_SCRIPT_NAME}.bash`)
+    path.join(COMPLETION_DIR, tabtabFileName('bash'))
   );
 
   await writeFile(bashrc, prevBashrc);
@@ -46,7 +47,7 @@ const afterWrites = (prevBashrc, prevScript) => async () => {
 const setupSuiteForInstall = async (shouldUseAfter = false) => {
   const files = {};
   const hook = shouldUseAfter ? after : afterEach;
-  const tabtabScript = path.join(COMPLETION_DIR, `${TABTAB_SCRIPT_NAME}.bash`);
+  const tabtabScript = path.join(COMPLETION_DIR, tabtabFileName('bash'));
 
   before(async () => {
     const { exists: bashrcExists, content: bashrcContent } = await readIfExists(
diff --git a/tsconfig.common.json b/tsconfig.common.json
new file mode 100644
index 0000000..0505ee4
--- /dev/null
+++ b/tsconfig.common.json
@@ -0,0 +1,9 @@
+{
+  "compilerOptions": {
+    "allowJs": true,
+    "checkJs": true,
+    "module": "Node16",
+    "strictNullChecks": true,
+    "target": "ES2022",
+  }
+}