Use strict types

package.json

@@ -34,17 +34,17 @@
     "remark-preset-wooorm": "^9.0.0",
     "rimraf": "^3.0.0",
     "tape": "^5.0.0",
+    "type-coverage": "^2.0.0",
     "typescript": "^4.0.0",
     "xo": "^0.45.0"
   },
   "scripts": {
-    "prepublishOnly": "npm run build",
+    "prepublishOnly": "npm run build && npm run format",
+    "build": "rimraf \"test/**/*.d.ts\" \"*.d.ts\" && tsc && type-coverage",
     "format": "remark . -qfo && prettier . -w --loglevel warn && xo --fix",
-    "prebuild": "rimraf \"*.d.ts\"",
-    "build": "tsc",
-    "test-api": "node test",
-    "test-coverage": "c8 --check-coverage --branches 100 --functions 100 --lines 100 --statements 100 --reporter lcov node test.js",
-    "test": "npm run format && npm run build && npm run test-coverage"
+    "test-api": "node --conditions development test.js",
+    "test-coverage": "c8 --check-coverage --branches 100 --functions 100 --lines 100 --statements 100 --reporter lcov npm run test-api",
+    "test": "npm run build && npm run format && npm run test-coverage"
   },
   "prettier": {
     "tabWidth": 2,
@@ -61,5 +61,11 @@
     "plugins": [
       "preset-wooorm"
     ]
+  },
+  "typeCoverage": {
+    "atLeast": 100,
+    "detail": true,
+    "strict": true,
+    "ignoreCatch": true
   }
 }

test.js

@@ -2,7 +2,7 @@ import test from 'tape'
 import {collapseWhiteSpace} from './index.js'
 
 test('collapseWhiteSpace(value)', function (t) {
-  // @ts-ignore runtime
+  // @ts-expect-error Incorrect `value`.
   t.equal(collapseWhiteSpace(true), 'true', 'should coerce to string')
 
   t.equal(collapseWhiteSpace(' \t\nbar \nbaz\t'), ' bar baz ')

tsconfig.json

@@ -1,5 +1,4 @@
 {
-  "files": ["index.js"],
   "include": ["*.js"],
   "compilerOptions": {
     "target": "ES2020",
@@ -11,6 +10,7 @@
     "declaration": true,
     "emitDeclarationOnly": true,
     "allowSyntheticDefaultImports": true,
-    "skipLibCheck": true
+    "skipLibCheck": true,
+    "strict": true
   }
 }