diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 46a7d93..ebcc68e 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -20,7 +20,7 @@ jobs:
       fail-fast: false
       matrix:
         os: [ubuntu-latest]
-        node-version: [10, 12, 14, 15, 16]
+        node-version: [18, 20]
         debug: [2, 3, 4]
     steps:
       - name: Checkout    
diff --git a/.gitignore b/.gitignore
index 3638b2e..d3d98cc 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,7 +1,10 @@
 node_modules/
+package-lock.json
 coverage/
 .nyc_output/
+.tap/
 tmp/
 npm-debug.log*
 .DS_Store
-.idea
\ No newline at end of file
+.idea
+.vscode
diff --git a/.npmignore b/.npmignore
index 2b5d81d..30480a2 100644
--- a/.npmignore
+++ b/.npmignore
@@ -1,3 +1,7 @@
 example/
 coverage/
-.nyc_output/
\ No newline at end of file
+.nyc_output/
+.tap/
+scripts/
+.github/
+test/
\ No newline at end of file
diff --git a/.nycrc.yml b/.nycrc.yml
new file mode 100644
index 0000000..ba8cb3d
--- /dev/null
+++ b/.nycrc.yml
@@ -0,0 +1,8 @@
+use-spawn-wrap: true
+include: [index.js, debug.js]
+reporter: [text, lcov, html]
+check-coverage: true
+statements: 100
+branches: 97
+functions: 100
+lines: 100
diff --git a/.taprc b/.taprc
index b293983..f626fe1 100644
--- a/.taprc
+++ b/.taprc
@@ -1,5 +1,4 @@
-esm: false
-ts: false
-jsx: false
-coverage: true
 timeout: 480
+reporter: terse
+include: [test/*.js]
+disable-coverage: true
diff --git a/benchmarks/basic.bench.js b/benchmarks/basic.bench.js
index ac83dde..203dd7d 100644
--- a/benchmarks/basic.bench.js
+++ b/benchmarks/basic.bench.js
@@ -1,13 +1,13 @@
 'use strict'
-var wrap = require('module').wrap
-var bench = require('fastbench')
-var pino = require('pino')
-var fs = require('fs')
-var dest = process.platform === 'win32' ? fs.createWriteStream('\\\\.\\NUL') : fs.createWriteStream('/dev/null')
-var plog = pino(dest)
+const wrap = require('module').wrap
+const bench = require('fastbench')
+let pino = require('pino')
+const fs = require('fs')
+const dest = process.platform === 'win32' ? fs.createWriteStream('\\\\.\\NUL') : fs.createWriteStream('/dev/null')
+const plog = pino(dest)
 
 process.env.DEBUG = 'dlog'
-var dlog = require('debug')('dlog')
+const dlog = require('debug')('dlog')
 dlog.log = function (s) { dest.write(s) }
 
 delete require.cache[require.resolve('debug')]
@@ -16,8 +16,8 @@ delete require.cache[require.resolve('debug/src/node')]
 
 delete require.cache[require.resolve('pino')]
 pino = require('pino')
-require('../')(pino({level: 'debug'}, dest))
-var pdlog = require('debug')('dlog')
+require('../')(pino({ level: 'debug' }, dest))
+const pdlog = require('debug')('dlog')
 
 delete require.cache[require.resolve('debug')]
 delete require.cache[require.resolve('debug/src/debug.js')]
@@ -28,31 +28,31 @@ require('module').wrap = wrap
 
 delete require.cache[require.resolve('pino')]
 pino = require('pino')
-require('../')(pino({extreme: true, level: 'debug'}, dest))
-var pedlog = require('debug')('dlog')
+require('../')(pino({ extreme: true, level: 'debug' }, dest))
+const pedlog = require('debug')('dlog')
 
-var max = 10
-var run = bench([
+const max = 10
+const run = bench([
   function benchPino (cb) {
-    for (var i = 0; i < max; i++) {
+    for (let i = 0; i < max; i++) {
       plog.info('hello world')
     }
     setImmediate(cb)
   },
   function benchDebug (cb) {
-    for (var i = 0; i < max; i++) {
+    for (let i = 0; i < max; i++) {
       dlog('hello world')
     }
     setImmediate(cb)
   },
   function benchPinoDebug (cb) {
-    for (var i = 0; i < max; i++) {
+    for (let i = 0; i < max; i++) {
       pdlog('hello world')
     }
     setImmediate(cb)
   },
   function benchPinoExtremeDebug (cb) {
-    for (var i = 0; i < max; i++) {
+    for (let i = 0; i < max; i++) {
       pedlog('hello world')
     }
     setImmediate(cb)
diff --git a/benchmarks/deep-object.bench.js b/benchmarks/deep-object.bench.js
index ff60da7..0b613bf 100644
--- a/benchmarks/deep-object.bench.js
+++ b/benchmarks/deep-object.bench.js
@@ -1,13 +1,13 @@
 'use strict'
-var wrap = require('module').wrap
-var bench = require('fastbench')
-var pino = require('pino')
-var fs = require('fs')
-var dest = process.platform === 'win32' ? fs.createWriteStream('\\\\.\\NUL') : fs.createWriteStream('/dev/null')
-var plog = pino(dest)
+const wrap = require('module').wrap
+const bench = require('fastbench')
+let pino = require('pino')
+const fs = require('fs')
+const dest = process.platform === 'win32' ? fs.createWriteStream('\\\\.\\NUL') : fs.createWriteStream('/dev/null')
+const plog = pino(dest)
 
 process.env.DEBUG = 'dlog'
-var dlog = require('debug')('dlog')
+const dlog = require('debug')('dlog')
 dlog.log = function (s) { dest.write(s) }
 
 delete require.cache[require.resolve('debug')]
@@ -16,8 +16,8 @@ delete require.cache[require.resolve('debug/src/node')]
 
 delete require.cache[require.resolve('pino')]
 pino = require('pino')
-require('../')(pino({level: 'debug'}, dest))
-var pdlog = require('debug')('dlog')
+require('../')(pino({ level: 'debug' }, dest))
+const pdlog = require('debug')('dlog')
 
 delete require.cache[require.resolve('debug')]
 delete require.cache[require.resolve('debug/src/debug.js')]
@@ -28,37 +28,37 @@ require('module').wrap = wrap
 
 delete require.cache[require.resolve('pino')]
 pino = require('pino')
-require('../')(pino({extreme: true, level: 'debug'}, dest))
-var pedlog = require('debug')('dlog')
+require('../')(pino({ extreme: true, level: 'debug' }, dest))
+const pedlog = require('debug')('dlog')
 
-var deep = require('../package.json')
+const deep = require('../package.json')
 deep.deep = Object.assign({}, JSON.parse(JSON.stringify(deep)))
 deep.deep.deep = Object.assign({}, JSON.parse(JSON.stringify(deep)))
 deep.deep.deep.deep = Object.assign({}, JSON.parse(JSON.stringify(deep)))
 
-var max = 10
+const max = 10
 
-var run = bench([
+const run = bench([
   function benchPinoDeepObj (cb) {
-    for (var i = 0; i < max; i++) {
+    for (let i = 0; i < max; i++) {
       plog.info(deep)
     }
     setImmediate(cb)
   },
   function benchDebugDeepObj (cb) {
-    for (var i = 0; i < max; i++) {
+    for (let i = 0; i < max; i++) {
       dlog(deep)
     }
     setImmediate(cb)
   },
   function benchPinoDebugDeepObj (cb) {
-    for (var i = 0; i < max; i++) {
+    for (let i = 0; i < max; i++) {
       pdlog(deep)
     }
     setImmediate(cb)
   },
   function benchPinoExtremeDebugDeepObj (cb) {
-    for (var i = 0; i < max; i++) {
+    for (let i = 0; i < max; i++) {
       pedlog(deep)
     }
     setImmediate(cb)
diff --git a/benchmarks/object.bench.js b/benchmarks/object.bench.js
index 96c7c31..8a0981b 100644
--- a/benchmarks/object.bench.js
+++ b/benchmarks/object.bench.js
@@ -1,13 +1,13 @@
 'use strict'
-var wrap = require('module').wrap
-var bench = require('fastbench')
-var pino = require('pino')
-var fs = require('fs')
-var dest = process.platform === 'win32' ? fs.createWriteStream('\\\\.\\NUL') : fs.createWriteStream('/dev/null')
-var plog = pino(dest)
+const wrap = require('module').wrap
+const bench = require('fastbench')
+let pino = require('pino')
+const fs = require('fs')
+const dest = process.platform === 'win32' ? fs.createWriteStream('\\\\.\\NUL') : fs.createWriteStream('/dev/null')
+const plog = pino(dest)
 
 process.env.DEBUG = 'dlog'
-var dlog = require('debug')('dlog')
+const dlog = require('debug')('dlog')
 dlog.log = function (s) { dest.write(s) }
 
 delete require.cache[require.resolve('debug')]
@@ -16,8 +16,8 @@ delete require.cache[require.resolve('debug/src/node')]
 
 delete require.cache[require.resolve('pino')]
 pino = require('pino')
-require('../')(pino({level: 'debug'}, dest))
-var pdlog = require('debug')('dlog')
+require('../')(pino({ level: 'debug' }, dest))
+const pdlog = require('debug')('dlog')
 
 delete require.cache[require.resolve('debug')]
 delete require.cache[require.resolve('debug/src/debug.js')]
@@ -26,33 +26,33 @@ delete require.cache[require.resolve('../')]
 delete require.cache[require.resolve('../debug')]
 require('module').wrap = wrap
 
-require('../')(pino({extreme: true, level: 'debug'}, dest))
-var pedlog = require('debug')('dlog')
+require('../')(pino({ extreme: true, level: 'debug' }, dest))
+const pedlog = require('debug')('dlog')
 
-var max = 10
+const max = 10
 
-var run = bench([
+const run = bench([
   function benchPinoObj (cb) {
-    for (var i = 0; i < max; i++) {
-      plog.info({hello: 'world'})
+    for (let i = 0; i < max; i++) {
+      plog.info({ hello: 'world' })
     }
     setImmediate(cb)
   },
   function benchDebugObj (cb) {
-    for (var i = 0; i < max; i++) {
-      dlog({hello: 'world'})
+    for (let i = 0; i < max; i++) {
+      dlog({ hello: 'world' })
     }
     setImmediate(cb)
   },
   function benchPinoDebugObj (cb) {
-    for (var i = 0; i < max; i++) {
-      pdlog({hello: 'world'})
+    for (let i = 0; i < max; i++) {
+      pdlog({ hello: 'world' })
     }
     setImmediate(cb)
   },
   function benchPinoExtremeDebugDeepObj (cb) {
-    for (var i = 0; i < max; i++) {
-      pedlog({hello: 'world'})
+    for (let i = 0; i < max; i++) {
+      pedlog({ hello: 'world' })
     }
     setImmediate(cb)
   }
diff --git a/benchmarks/runbench.js b/benchmarks/runbench.js
index f6400f0..fea6c84 100644
--- a/benchmarks/runbench.js
+++ b/benchmarks/runbench.js
@@ -1,12 +1,12 @@
 'use strict'
 
-var fs = require('fs')
-var path = require('path')
-var spawn = require('child_process').spawn
-var pump = require('pump')
-var split = require('split2')
-var through = require('through2')
-var steed = require('steed')
+const fs = require('fs')
+const path = require('path')
+const spawn = require('child_process').spawn
+const pump = require('pump')
+const split = require('split2')
+const through = require('through2')
+const steed = require('steed')
 
 function usage () {
   return fs.createReadStream(path.join(__dirname, 'usage.txt'))
@@ -17,22 +17,22 @@ if (!process.argv[2]) {
   process.exit()
 }
 
-var selectedBenchmark = process.argv[2].toLowerCase()
-var benchmarkDir = path.resolve(__dirname)
-var benchmarks = {
+let selectedBenchmark = process.argv[2].toLowerCase()
+const benchmarkDir = path.resolve(__dirname)
+const benchmarks = {
   basic: 'basic.bench.js',
   object: 'object.bench.js',
   deepobject: 'deep-object.bench.js'
 }
 
 function runBenchmark (name, done) {
-  var benchmarkResults = {}
+  const benchmarkResults = {}
   benchmarkResults[name] = {}
 
-  var processor = through(function (line, enc, cb) {
-    var parts = ('' + line).split(': ')
-    var parts2 = parts[0].split('*')
-    var logger = parts2[0].replace('bench', '')
+  const processor = through(function (line, enc, cb) {
+    const parts = ('' + line).split(': ')
+    const parts2 = parts[0].split('*')
+    const logger = parts2[0].replace('bench', '')
 
     if (!benchmarkResults[name][logger]) benchmarkResults[name][logger] = []
 
@@ -45,7 +45,7 @@ function runBenchmark (name, done) {
   })
 
   console.log('Running ' + name.toUpperCase() + ' benchmark\n')
-  var benchmark = spawn(
+  const benchmark = spawn(
     process.argv[0],
     [path.join(benchmarkDir, benchmarks[name])]
   )
@@ -60,8 +60,8 @@ function runBenchmark (name, done) {
 }
 
 function sum (ar) {
-  var result = 0
-  for (var i = 0; i < ar.length; i += 1) {
+  let result = 0
+  for (let i = 0; i < ar.length; i += 1) {
     result += Number.parseFloat(ar[i].time)
   }
   return result
@@ -69,14 +69,14 @@ function sum (ar) {
 
 function displayResults (results) {
   console.log('==========')
-  var benchNames = Object.keys(results)
-  for (var i = 0; i < benchNames.length; i += 1) {
+  const benchNames = Object.keys(results)
+  for (let i = 0; i < benchNames.length; i += 1) {
     console.log(benchNames[i] + ' averages')
-    var benchmark = results[benchNames[i]]
-    var loggers = Object.keys(benchmark)
-    for (var j = 0; j < loggers.length; j += 1) {
-      var logger = benchmark[loggers[j]]
-      var average = Math.round(sum(logger) / logger.length)
+    const benchmark = results[benchNames[i]]
+    const loggers = Object.keys(benchmark)
+    for (let j = 0; j < loggers.length; j += 1) {
+      const logger = benchmark[loggers[j]]
+      const average = Math.round(sum(logger) / logger.length)
       console.log(loggers[j] + ' average: ' + average)
     }
   }
@@ -87,14 +87,14 @@ function toBench (done) {
   runBenchmark(this.name, done)
 }
 
-var benchQueue = []
+const benchQueue = []
 if (selectedBenchmark !== 'all') {
-  benchQueue.push(toBench.bind({name: selectedBenchmark}))
+  benchQueue.push(toBench.bind({ name: selectedBenchmark }))
 } else {
-  var keys = Object.keys(benchmarks)
-  for (var i = 0; i < keys.length; i += 1) {
+  const keys = Object.keys(benchmarks)
+  for (let i = 0; i < keys.length; i += 1) {
     selectedBenchmark = keys[i]
-    benchQueue.push(toBench.bind({name: selectedBenchmark}))
+    benchQueue.push(toBench.bind({ name: selectedBenchmark }))
   }
 }
 steed.series(benchQueue, function (err, results) {
diff --git a/debug.js b/debug.js
index 3f186f4..3b80634 100644
--- a/debug.js
+++ b/debug.js
@@ -8,8 +8,8 @@ function debug (namespace) {
    'register pino-debug at the top of your entry point')
   }
 
-  var logger = debug.logger.child({'ns': namespace})
-  var log = Array.from(debug.map.keys()).map(function (rx) {
+  const logger = debug.logger.child({ ns: namespace })
+  const log = Array.from(debug.map.keys()).map(function (rx) {
     return rx.test(namespace) && logger[debug.map.get(rx)]
   }).filter(Boolean)[0] || logger.debug
 
@@ -20,7 +20,7 @@ function debug (namespace) {
   }
   enabled.enabled = true
 
-  var fn = debug.enabled(namespace) ? enabled : disabled
+  const fn = debug.enabled(namespace) ? enabled : disabled
   fn.extend = function (subNamespace, delimiter) {
     return debug(namespace + (delimiter || ':') + subNamespace)
   }
diff --git a/example/app.js b/example/app.js
index d1dbd2d..f6553c3 100644
--- a/example/app.js
+++ b/example/app.js
@@ -1,13 +1,13 @@
-var express = require('express')
-var path = require('path')
-var logger = require('morgan')
-var cookieParser = require('cookie-parser')
-var bodyParser = require('body-parser')
+const express = require('express')
+const path = require('path')
+const logger = require('morgan')
+const cookieParser = require('cookie-parser')
+const bodyParser = require('body-parser')
 
-var index = require('./routes/index')
-var users = require('./routes/users')
+const index = require('./routes/index')
+const users = require('./routes/users')
 
-var app = express()
+const app = express()
 
 // view engine setup
 app.set('views', path.join(__dirname, 'views'))
@@ -24,7 +24,7 @@ app.use('/users', users)
 
 // catch 404 and forward to error handler
 app.use(function (req, res, next) {
-  var err = new Error('Not Found')
+  const err = new Error('Not Found')
   err.status = 404
   next(err)
 })
diff --git a/example/routes/index.js b/example/routes/index.js
index a306a5c..4092548 100644
--- a/example/routes/index.js
+++ b/example/routes/index.js
@@ -1,5 +1,5 @@
-var express = require('express')
-var router = express.Router()
+const express = require('express')
+const router = express.Router()
 /* GET home page. */
 router.get('/', function (req, res, next) {
   res.render('index', { title: 'Express' })
diff --git a/example/routes/users.js b/example/routes/users.js
index 8cfe88f..f37ae1b 100644
--- a/example/routes/users.js
+++ b/example/routes/users.js
@@ -1,5 +1,5 @@
-var express = require('express')
-var router = express.Router()
+const express = require('express')
+const router = express.Router()
 
 /* GET users listing. */
 router.get('/', function (req, res, next) {
diff --git a/index.js b/index.js
index 8d5ff0d..f5b70b6 100644
--- a/index.js
+++ b/index.js
@@ -1,11 +1,12 @@
 'use strict'
 
-var pino = require('pino')
+const pino = require('pino')
 require('module').wrap = override
-var debug = require('debug')
+const debug = require('debug')
 
 module.exports = pinoDebug
 
+/* istanbul ignore next */
 if (module.parent && module.parent.parent === null && module.parent.filename === null) {
   // preloaded with -r flag
   pinoDebug()
@@ -15,15 +16,15 @@ function pinoDebug (logger, opts) {
   if (pinoDebug.called) throw Error('pino-debug can only be called once')
   pinoDebug.called = true
   opts = opts || {}
-  var auto = 'auto' in opts ? opts.auto : true
-  var map = opts.map || {}
-  var namespaces = getNamespaces()
+  const auto = 'auto' in opts ? opts.auto : true
+  const map = opts.map || {}
+  const namespaces = getNamespaces()
   debug.map = Object.keys(map).sort(byPrecision).reduce(function (m, k) {
     if (auto) namespaces.push(k)
     m.set(RegExp('^' + k.replace(/[\\^$+?.()|[\]{}]/g, '\\$&').replace(/\*/g, '.*?') + '$'), map[k])
     return m
   }, new Map())
-  debug.logger = logger || pino({level: 'debug'})
+  debug.logger = logger || pino({ level: 'debug' })
   if (opts.skip) {
     opts.skip.map(function (ns) { return '-' + ns }).forEach(function (ns) { namespaces.push(ns) })
   }
@@ -31,7 +32,7 @@ function pinoDebug (logger, opts) {
 }
 
 function getNamespaces () {
-  var namespaces = process.env.DEBUG
+  const namespaces = process.env.DEBUG
   if (namespaces != null) {
     return (typeof namespaces === 'string' ? namespaces : '').split(/[\s,]+/)
   }
@@ -39,8 +40,8 @@ function getNamespaces () {
 }
 
 function byPrecision (a, b) {
-  var aix = a.indexOf('*')
-  var bix = b.indexOf('*')
+  const aix = a.indexOf('*')
+  const bix = b.indexOf('*')
   if (aix === -1 && bix === -1) return 0
   if (~aix && ~bix) {
     if (aix > bix) return -1
@@ -57,9 +58,9 @@ function override (script) {
   // F:\Projekty\Learn\pino-debug\debug.js) will be interpreted during interpolation
   // as F:ProjektyLearnpino-debugdebug.js and node.js will throw error
   // Cannot find module 'F:ProjektyLearnpino-debugdebug.js'
-  var pathToPinoDebug = require.resolve('./debug').replace(/\\/g, '\\\\')
+  const pathToPinoDebug = require.resolve('./debug').replace(/\\/g, '\\\\')
 
-  var head = `(function(exports, require, module, __filename, __dirname) {
+  const head = `(function(exports, require, module, __filename, __dirname) {
       require = (function (req) {
         var pinoDebugOs = require('os')
         var pinoDebugPath = require('path')
@@ -99,7 +100,7 @@ function override (script) {
       }(require))
       return (function(){
   `.trim().replace(/\n/g, ';').replace(/\s+/g, ' ').replace(/;+/g, ';')
-  var tail = '\n}).call(this);})'
+  const tail = '\n}).call(this);})'
 
   return head + script + tail
 }
diff --git a/package.json b/package.json
index aacfc30..1326227 100644
--- a/package.json
+++ b/package.json
@@ -4,16 +4,21 @@
   "description": "High performance debug logging",
   "main": "index.js",
   "scripts": {
-    "test": "dependency-check --no-dev . && cross-env NODE_ENV=test tap test/*.js",
-    "test-2.3": "npm i debug@2.3 && npm run test",
-    "test-2.4": "npm i debug@2.4 && npm run test",
-    "test-2.5": "npm i debug@2.5 && npm run test",
-    "test-2.6": "npm i debug@2.6 && npm run test",
-    "test-3.1": "npm i debug@3.1 && npm run test",
-    "test-4.1": "npm i debug@4.1 && npm run test",
-    "test:cov": "standard && npm run deps && cross-env NODE_ENV=test tap --cov test/*.js",
-    "ci": "npm test -- --coverage-report=lcov",
-    "test:cov:html": "standard && npm run deps && cross-env NODE_ENV=test tap --coverage-report=html test",
+    "test": "npm run deps && standard && npm run test:unit",
+    "deps": "knip --production --dependencies",
+    "standard": "standard",
+    "standard:fix": "standard --fix",
+    "test:unit": "cross-env NODE_ENV=test nyc tap",
+    "test:watch": "cross-env NODE_ENV=test tap repl w",
+    "test:with-debug": "npm i --no-save --no-audit --no-fund debug@$DEBUG_VERSION && npm run test:unit -- --after scripts/npmi",
+    "test-2.3": "cross-env DEBUG_VERSION=2.3 npm run test:with-debug",
+    "test-2.4": "cross-env DEBUG_VERSION=2.4 npm run test:with-debug",
+    "test-2.5": "cross-env DEBUG_VERSION=2.5 npm run test:with-debug",
+    "test-2.6": "cross-env DEBUG_VERSION=2.6 npm run test:with-debug",
+    "test-3.1": "cross-env DEBUG_VERSION=3.1 npm run test:with-debug",
+    "test-4.1": "cross-env DEBUG_VERSION=4.1 npm run test:with-debug",
+    "test-all": "npm run test-2.3 && npm run test-2.4 && npm run test-2.5 && npm run test-2.6 && npm run test-3.1 && npm run test-4.1",
+    "ci": "npm test",
     "bench": "node benchmarks/runbench all",
     "bench-basic": "node benchmarks/runbench basic",
     "bench-object": "node benchmarks/runbench object",
@@ -31,20 +36,21 @@
   ],
   "license": "MIT",
   "dependencies": {
-    "pino": "^6.0.2"
+    "pino": "^8.0.0"
   },
   "peerDependencies": {
     "debug": ">=2"
   },
   "devDependencies": {
     "cross-env": "^7.0.3",
-    "dependency-check": "^4.0.0",
     "fastbench": "^1.0.1",
+    "knip": "^5.1.2",
+    "nyc": "^15.1.0",
     "pump": "^3.0.0",
-    "split2": "^4.0.0",
-    "standard": "^17.0.0",
+    "split2": "^4.2.0",
+    "standard": "^17.1.0",
     "steed": "^1.1.3",
-    "tap": "^14.0.0",
-    "through2": "^4.0.0"
+    "tap": "^18.7.1",
+    "through2": "^4.0.2"
   }
 }
diff --git a/scripts/npmi.js b/scripts/npmi.js
new file mode 100644
index 0000000..119b586
--- /dev/null
+++ b/scripts/npmi.js
@@ -0,0 +1,3 @@
+// Cleanup after testing specific debug version
+const { spawnSync } = require('child_process')
+spawnSync('npm', ['i'], { stdio: 'ignore' })
diff --git a/test/fixtures/line-numbers.js b/test/fixtures/line-numbers.js
index 1519fd0..1a29c14 100644
--- a/test/fixtures/line-numbers.js
+++ b/test/fixtures/line-numbers.js
@@ -1,8 +1,8 @@
 module.exports = function lineNum () {
-  var orig = Error.prepareStackTrace
+  const orig = Error.prepareStackTrace
   Error.prepareStackTrace = function (_, stack) { return stack }
-  var err = new Error()
-  var stack = err.stack
+  const err = new Error()
+  const stack = err.stack
   Error.prepareStackTrace = orig
   return stack[0].getLineNumber()
 }
diff --git a/test/fixtures/object-override.js b/test/fixtures/object-override.js
index c1821c1..95f9870 100644
--- a/test/fixtures/object-override.js
+++ b/test/fixtures/object-override.js
@@ -1,5 +1,5 @@
 'use strict'
 // stylus literally does this -- https://git.io/vyPlO
-var Object = function Object () {}
+const Object = function Object () {}
 
 module.exports = Object
diff --git a/test/fixtures/strict-mode.js b/test/fixtures/strict-mode.js
index 8e315a1..e6ee2ae 100644
--- a/test/fixtures/strict-mode.js
+++ b/test/fixtures/strict-mode.js
@@ -1,5 +1,6 @@
 'use strict'
 
+/* eslint-disable-next-line */
 eval('var test = 123')
 
 // This will evaluate to `true` if strict mode is enabled
diff --git a/test/index.js b/test/index.js
index 37345bd..69a8b19 100644
--- a/test/index.js
+++ b/test/index.js
@@ -1,8 +1,10 @@
 'use strict'
-var execSync = require('child_process').execSync
-var tap = require('tap')
-var through = require('through2')
-var test = tap.test
+
+const path = require('path')
+const { exec, execSync } = require('child_process')
+const tap = require('tap')
+const through = require('through2')
+const test = tap.test
 
 const debugModules = [
   // <= 2.4
@@ -29,7 +31,7 @@ const commonModules = [
   './'
 ]
 
-tap.afterEach((done) => {
+tap.afterEach(() => {
   let err = null
   for (const modules of debugModules) {
     try {
@@ -46,12 +48,11 @@ tap.afterEach((done) => {
     throw err
   }
   process.env.DEBUG = ''
-  done()
 })
 
 test('throws if called more than once', (t) => {
-  var pinoDebug = require('../')
-  t.throw(() => {
+  const pinoDebug = require('../')
+  t.throws(() => {
     pinoDebug()
     pinoDebug()
   })
@@ -60,86 +61,93 @@ test('throws if called more than once', (t) => {
 
 test('throws if debug is called after requiring but before calling pinoDebug', (t) => {
   require('../')
-  var debug = require('debug')
-  t.throw(() => debug('ns'))
+  const debug = require('debug')
+  t.throws(() => debug('ns'))
   t.end()
 })
 
 test('captures any calls to `debug` and passes them through pino logger', (t) => {
-  var pinoDebug = require('../')
-  var stream = through((line, _, cb) => {
-    var obj = JSON.parse(line)
-    t.is(obj.msg, 'test')
-    t.is(obj.ns, 'ns')
+  const pinoDebug = require('../')
+  const stream = through((line, _, cb) => {
+    const obj = JSON.parse(line)
+    t.equal(obj.msg, 'test')
+    t.equal(obj.ns, 'ns')
     t.end()
   })
-  pinoDebug(require('pino')({level: 'debug'}, stream))
-  var debug = require('debug')
+  pinoDebug(require('pino')({ level: 'debug' }, stream))
+  const debug = require('debug')
   debug.enable('ns')
   debug('ns')('test')
 })
 
 test('defaults to calling pinoInstance.debug', (t) => {
-  var pinoDebug = require('../')
-  var stream = through((line, _, cb) => {
-    var obj = JSON.parse(line)
-    t.is(obj.msg, 'test')
-    t.is(obj.ns, 'ns')
-    t.is(obj.level, 20)
+  const pinoDebug = require('../')
+  const stream = through((line, _, cb) => {
+    const obj = JSON.parse(line)
+    t.equal(obj.msg, 'test')
+    t.equal(obj.ns, 'ns')
+    t.equal(obj.level, 20)
     t.end()
   })
-  pinoDebug(require('pino')({level: 'debug'}, stream))
-  var debug = require('debug')
+  pinoDebug(require('pino')({ level: 'debug' }, stream))
+  const debug = require('debug')
   debug.enable('ns')
   debug('ns')('test')
 })
 
 test('when passed no args, creates a standard pino logger with log level set to debug and logs to it\'s debug method', (t) => {
-  var program = `
-    var pinoDebug = require('${__dirname}/../')
+  const debug = path.join(__dirname, '..')
+  const program = `
+    var pinoDebug = require('${debug}')
     var write = process.stdout.write
     pinoDebug()
     var debug = require('debug')
     debug.enable('ns')
     debug('ns')('test')
   `
-  var line = execSync(`${process.argv[0]} -e "${program}"`).toString()
-  var obj = JSON.parse(line)
-  t.is(obj.msg, 'test')
-  t.is(obj.ns, 'ns')
-  t.is(obj.level, 20)
-  t.end()
+
+  exec(`${process.argv[0]} -e "${program}"`, (err, stdout, stderr) => {
+    t.error(err)
+    console.log(stdout.toString())
+    console.log(stderr.toString())
+    const line = stdout.toString()
+    const obj = JSON.parse(line)
+    t.equal(obj.msg, 'test')
+    t.equal(obj.ns, 'ns')
+    t.equal(obj.level, 20)
+    t.end()
+  })
 })
 
 test('passes debug args to pino log method according to opts.map', (t) => {
-  var pinoDebug = require('../')
-  var stream = through((line, _, cb) => {
-    var obj = JSON.parse(line)
-    t.is(obj.msg, 'test')
-    t.is(obj.ns, 'ns')
-    t.is(obj.level, 30)
+  const pinoDebug = require('../')
+  const stream = through((line, _, cb) => {
+    const obj = JSON.parse(line)
+    t.equal(obj.msg, 'test')
+    t.equal(obj.ns, 'ns')
+    t.equal(obj.level, 30)
     t.end()
   })
-  pinoDebug(require('pino')(stream), {map: {ns: 'info'}})
-  var debug = require('debug')
+  pinoDebug(require('pino')(stream), { map: { ns: 'info' } })
+  const debug = require('debug')
   debug('ns')('test')
 })
 
 test('passes debug args to pino log method according to opts.map when auto is off but namespaces have been enabled', (t) => {
-  var pinoDebug = require('../')
-  var ns = (line) => {
-    var obj = JSON.parse(line)
-    t.is(obj.msg, 'test')
-    t.is(obj.ns, 'ns')
-    t.is(obj.level, 30)
+  const pinoDebug = require('../')
+  const ns = (line) => {
+    const obj = JSON.parse(line)
+    t.equal(obj.msg, 'test')
+    t.equal(obj.ns, 'ns')
+    t.equal(obj.level, 30)
   }
-  var ns2 = (line) => {
-    var obj = JSON.parse(line)
-    t.is(obj.msg, 'test2')
-    t.is(obj.ns, 'ns2')
-    t.is(obj.level, 40)
+  const ns2 = (line) => {
+    const obj = JSON.parse(line)
+    t.equal(obj.msg, 'test2')
+    t.equal(obj.ns, 'ns2')
+    t.equal(obj.level, 40)
   }
-  var stream = through((line, _, cb) => {
+  const stream = through((line, _, cb) => {
     if (!ns.called) {
       ns(line)
       ns.called = true
@@ -150,8 +158,8 @@ test('passes debug args to pino log method according to opts.map when auto is of
     t.end()
   })
 
-  pinoDebug(require('pino')(stream), {auto: false, map: {ns: 'info', ns2: 'warn'}})
-  var debug = require('debug')
+  pinoDebug(require('pino')(stream), { auto: false, map: { ns: 'info', ns2: 'warn' } })
+  let debug = require('debug')
   debug.enable('ns')
   debug('ns')('test')
   debug = require('debug')
@@ -160,110 +168,111 @@ test('passes debug args to pino log method according to opts.map when auto is of
 })
 
 test('does not pass debug args to pino log method according to opts.map when auto is off and namespaces have not been enabled', (t) => {
-  var pinoDebug = require('../')
+  const pinoDebug = require('../')
 
-  var stream = through((line, _, cb) => {
-    var obj = JSON.parse(line)
-    t.is(obj.msg, 'test2')
-    t.is(obj.ns, 'ns2')
-    t.is(obj.level, 40)
+  const stream = through((line, _, cb) => {
+    const obj = JSON.parse(line)
+    t.equal(obj.msg, 'test2')
+    t.equal(obj.ns, 'ns2')
+    t.equal(obj.level, 40)
     t.end()
     cb()
   })
 
-  pinoDebug(require('pino')(stream), {auto: false, map: {ns: 'info', ns2: 'warn'}})
-  var debug = require('debug')
+  pinoDebug(require('pino')(stream), { auto: false, map: { ns: 'info', ns2: 'warn' } })
+  const debug = require('debug')
   debug.enable('ns2')
   debug('ns')('test')
   debug('ns2')('test2')
 })
 
 test('when preloaded with -r, automatically logs all debug calls with log level debug to a default pino logger', (t) => {
-  var program = `
+  const program = `
     var debug = require('debug')
     debug('ns')('test')
   `
-  var line = execSync(`${process.argv[0]} -r ${__dirname}/../ -e "${program}"`, {env: {DEBUG: '*'}}).toString()
-  var obj = JSON.parse(line)
-  t.is(obj.msg, 'test')
-  t.is(obj.ns, 'ns')
-  t.is(obj.level, 20)
+  const debug = path.join(__dirname, '..')
+  const line = execSync(`${process.argv[0]} -r ${debug} -e "${program}"`, { env: { DEBUG: '*' } }).toString()
+  const obj = JSON.parse(line)
+  t.equal(obj.msg, 'test')
+  t.equal(obj.ns, 'ns')
+  t.equal(obj.level, 20)
   t.end()
 })
 
 test('opts.skip filters out any matching namespaces', (t) => {
-  var pinoDebug = require('../')
+  const pinoDebug = require('../')
 
-  var stream = through((line, _, cb) => {
-    var obj = JSON.parse(line)
-    t.is(obj.msg, 'test')
-    t.is(obj.ns, 'ns')
-    t.is(obj.level, 30)
+  const stream = through((line, _, cb) => {
+    const obj = JSON.parse(line)
+    t.equal(obj.msg, 'test')
+    t.equal(obj.ns, 'ns')
+    t.equal(obj.level, 30)
     t.end()
     cb()
   })
 
   pinoDebug(require('pino')(stream), {
-    map: {'ns*': 'info'},
+    map: { 'ns*': 'info' },
     skip: ['ns2']
   })
-  var debug = require('debug')
+  const debug = require('debug')
   debug('ns2')('test2')
   debug('ns')('test')
 })
 
 test('when there is a match conflict, log level is set to most precise match', (t) => {
-  var pinoDebug = require('../')
+  const pinoDebug = require('../')
 
-  var queue = [(line) => {
-    var obj = JSON.parse(line)
-    t.is(obj.msg, 'test')
-    t.is(obj.ns, 'ns')
-    t.is(obj.level, 30)
+  const queue = [(line) => {
+    const obj = JSON.parse(line)
+    t.equal(obj.msg, 'test')
+    t.equal(obj.ns, 'ns')
+    t.equal(obj.level, 30)
   }, (line) => {
-    var obj = JSON.parse(line)
-    t.is(obj.msg, 'test2')
-    t.is(obj.ns, 'ns2')
-    t.is(obj.level, 40)
+    const obj = JSON.parse(line)
+    t.equal(obj.msg, 'test2')
+    t.equal(obj.ns, 'ns2')
+    t.equal(obj.level, 40)
   }, (line) => {
-    var obj = JSON.parse(line)
-    t.is(obj.msg, 'test3')
-    t.is(obj.ns, 'meow')
-    t.is(obj.level, 50)
+    const obj = JSON.parse(line)
+    t.equal(obj.msg, 'test3')
+    t.equal(obj.ns, 'meow')
+    t.equal(obj.level, 50)
   }, (line) => {
-    var obj = JSON.parse(line)
-    t.is(obj.msg, 'test4')
-    t.is(obj.ns, 'izikilla')
-    t.is(obj.level, 60)
+    const obj = JSON.parse(line)
+    t.equal(obj.msg, 'test4')
+    t.equal(obj.ns, 'izikilla')
+    t.equal(obj.level, 60)
   }, (line) => {
-    var obj = JSON.parse(line)
-    t.is(obj.msg, 'test5')
-    t.is(obj.ns, 'testtracetest')
-    t.is(obj.level, 10)
+    const obj = JSON.parse(line)
+    t.equal(obj.msg, 'test5')
+    t.equal(obj.ns, 'testtracetest')
+    t.equal(obj.level, 10)
   }, (line) => {
-    var obj = JSON.parse(line)
-    t.is(obj.msg, 'test6')
-    t.is(obj.ns, 'debugtra')
-    t.is(obj.level, 20)
+    const obj = JSON.parse(line)
+    t.equal(obj.msg, 'test6')
+    t.equal(obj.ns, 'debugtra')
+    t.equal(obj.level, 20)
   }, (line) => {
-    var obj = JSON.parse(line)
-    t.is(obj.msg, 'test7')
-    t.is(obj.ns, 'ns3')
-    t.is(obj.level, 20)
+    const obj = JSON.parse(line)
+    t.equal(obj.msg, 'test7')
+    t.equal(obj.ns, 'ns3')
+    t.equal(obj.level, 20)
   }, (line) => {
-    var obj = JSON.parse(line)
-    t.is(obj.msg, 'test8')
-    t.is(obj.ns, 'testbla')
-    t.is(obj.level, 30)
+    const obj = JSON.parse(line)
+    t.equal(obj.msg, 'test8')
+    t.equal(obj.ns, 'testbla')
+    t.equal(obj.level, 30)
   }]
 
-  var stream = through((line, _, cb) => {
+  const stream = through((line, _, cb) => {
     queue.shift()(line)
     cb()
     if (!queue.length) t.end()
   })
 
-  pinoDebug(require('pino')({level: 'trace'}, stream), {
+  pinoDebug(require('pino')({ level: 'trace' }, stream), {
     map: {
       '*tra': 'debug',
       '*bla': 'info',
@@ -275,7 +284,7 @@ test('when there is a match conflict, log level is set to most precise match', (
       '*trace*': 'trace'
     }
   })
-  var debug = require('debug')
+  const debug = require('debug')
   debug('ns')('test')
   debug('ns2')('test2')
   debug('meow')('test3')
@@ -293,9 +302,9 @@ test('uses native `Object` regardless of wrapped file contents', (t) => {
 
 test('keeps line numbers consistent', (t) => {
   require('../')
-  var lineNums = require('./fixtures/line-numbers')
-  var line = lineNums()
-  t.is(line, 4)
+  const lineNums = require('./fixtures/line-numbers')
+  const line = lineNums()
+  t.equal(line, 4)
 
   t.end()
 })
@@ -307,31 +316,31 @@ test('results in valid syntax when source has trailing comment', (t) => {
 
 test('preserves DEBUG env independently from debug module', (t) => {
   process.env.DEBUG = 'ns1'
-  var pinoDebug = require('../')
-  var stream = through((line, _, cb) => {
-    var obj = JSON.parse(line)
-    t.is(obj.msg, 'test')
-    t.is(obj.ns, 'ns1')
+  const pinoDebug = require('../')
+  const stream = through((line, _, cb) => {
+    const obj = JSON.parse(line)
+    t.equal(obj.msg, 'test')
+    t.equal(obj.ns, 'ns1')
     t.end()
   })
-  pinoDebug(require('pino')({level: 'debug'}, stream))
-  var debug = require('debug')
+  pinoDebug(require('pino')({ level: 'debug' }, stream))
+  const debug = require('debug')
   debug('ns1')('test')
 })
 
 test('supports extend method', (t) => {
   process.env.DEBUG = '*'
-  var pinoDebug = require('../')
-  var ns = ['ns1', 'ns1:ns2', 'ns1;ns2']
-  var count = 0
-  var stream = through((line, _, cb) => {
-    var obj = JSON.parse(line)
-    t.is(obj.msg, 'test')
-    t.is(obj.ns, ns[count++])
+  const pinoDebug = require('../')
+  const ns = ['ns1', 'ns1:ns2', 'ns1;ns2']
+  let count = 0
+  const stream = through((line, _, cb) => {
+    const obj = JSON.parse(line)
+    t.equal(obj.msg, 'test')
+    t.equal(obj.ns, ns[count++])
     cb()
   }, () => t.end())
-  pinoDebug(require('pino')({level: 'debug'}, stream))
-  var debug = require('debug')
+  pinoDebug(require('pino')({ level: 'debug' }, stream))
+  const debug = require('debug')
   debug('ns1')('test')
   debug('ns1').extend('ns2')('test')
   debug('ns1').extend('ns2', ';')('test')
@@ -339,6 +348,6 @@ test('supports extend method', (t) => {
 })
 
 test('does not invalidate strict mode', (t) => {
-  t.is(require('./fixtures/strict-mode'), true)
+  t.equal(require('./fixtures/strict-mode'), true)
   t.end()
 })