refactor: replace some lodash usage with native (#1685)

For: #1285

Not logic changes, just making use of newer JS.

lib/back.js

@@ -154,15 +154,11 @@ const record = {
     const context = load(fixture, options)
 
     if (!context.isLoaded) {
-      recorder.record(
-        _.assign(
-          {
-            dont_print: true,
-            output_objects: true,
-          },
-          options && options.recorder
-        )
-      )
+      recorder.record({
+        dont_print: true,
+        output_objects: true,
+        ...options.recorder,
+      })
 
       context.isRecording = true
     }

lib/common.js

@@ -214,13 +214,9 @@ const headersFieldNamesToLowerCase = function(headers) {
   return lowerCaseHeaders
 }
 
-const headersFieldsArrayToLowerCase = function(headers) {
-  return _.uniq(
-    _.map(headers, function(fieldName) {
-      return fieldName.toLowerCase()
-    })
-  )
-}
+const headersFieldsArrayToLowerCase = headers => [
+  ...new Set(headers.map(fieldName => fieldName.toLowerCase())),
+]
 
 /**
  * Converts the various accepted formats of headers into a flat array representing "raw headers".
@@ -421,10 +417,12 @@ function percentEncode(str) {
 }
 
 function matchStringOrRegexp(target, pattern) {
-  const str =
-    (!_.isUndefined(target) && target.toString && target.toString()) || ''
+  const targetStr =
+    target === undefined || target === null ? '' : String(target)
 
-  return pattern instanceof RegExp ? pattern.test(str) : str === String(pattern)
+  return pattern instanceof RegExp
+    ? pattern.test(targetStr)
+    : targetStr === String(pattern)
 }
 
 /**
@@ -444,8 +442,8 @@ function formatQueryValue(key, value, stringFormattingFn) {
     case _.isBoolean(value):
       value = value.toString()
       break
-    case _.isNull(value): // fall-through
-    case _.isUndefined(value):
+    case value === null:
+    case value === undefined:
       value = ''
       break
     case _.isString(value):
@@ -455,7 +453,7 @@ function formatQueryValue(key, value, stringFormattingFn) {
       break
     case value instanceof RegExp:
       break
-    case _.isArray(value): {
+    case Array.isArray(value): {
       value = value.map(function(val, idx) {
         return formatQueryValue(idx, val, stringFormattingFn)[1]
       })

lib/intercept.js

@@ -332,43 +332,24 @@ function restoreOverriddenClientRequest() {
 function isActive() {
   //  If ClientRequest has been overwritten by Nock then originalClientRequest is not undefined.
   //  This means that Nock has been activated.
-  return !_.isUndefined(originalClientRequest)
+  return originalClientRequest !== undefined
 }
 
 function interceptorScopes() {
-  return _.reduce(
-    allInterceptors,
-    function(result, interceptors) {
-      for (const interceptor in interceptors.scopes) {
-        result = result.concat(interceptors.scopes[interceptor].__nock_scope)
-      }
-
-      return result
-    },
-    []
-  )
+  const nestedInterceptors = Object.values(allInterceptors).map(i => i.scopes)
+  return [].concat(...nestedInterceptors).map(i => i.scope)
 }
 
 function isDone() {
-  return _.every(interceptorScopes(), function(scope) {
-    return scope.isDone()
-  })
+  return interceptorScopes().every(scope => scope.isDone())
 }
 
 function pendingMocks() {
-  return _.flatten(
-    _.map(interceptorScopes(), function(scope) {
-      return scope.pendingMocks()
-    })
-  )
+  return [].concat(...interceptorScopes().map(scope => scope.pendingMocks()))
 }
 
 function activeMocks() {
-  return _.flatten(
-    _.map(interceptorScopes(), function(scope) {
-      return scope.activeMocks()
-    })
-  )
+  return [].concat(...interceptorScopes().map(scope => scope.activeMocks()))
 }
 
 function activate() {

lib/interceptor.js

@@ -205,7 +205,7 @@ module.exports = class Interceptor {
       return true
     }
 
-    if (!_.isUndefined(reqHeader) && !_.isUndefined(header)) {
+    if (reqHeader !== undefined && header !== undefined) {
       if (_.isFunction(reqHeader)) {
         return reqHeader(header)
       } else if (common.matchStringOrRegexp(header, reqHeader)) {

lib/request_overrider.js

@@ -73,9 +73,7 @@ class InterceptedRequestHandler {
       // affecting the user so we use a clone of the object.
       ...options,
       // We use lower-case header field names throughout Nock.
-      headers: options.headers
-        ? common.headersFieldNamesToLowerCase(options.headers)
-        : undefined,
+      headers: common.headersFieldNamesToLowerCase(options.headers || {}),
     }
 
     this.interceptors = interceptors
@@ -94,13 +92,11 @@ class InterceptedRequestHandler {
 
     const { options } = this
 
-    if (options.headers) {
-      _.forOwn(options.headers, (val, key) => {
-        setHeader(req, key, val)
-      })
+    for (const [name, val] of Object.entries(options.headers)) {
+      setHeader(req, name, val)
     }
 
-    if (options.auth && (!options.headers || !options.headers.authorization)) {
+    if (options.auth && !options.headers.authorization) {
       setHeader(
         req,
         'Authorization',

lib/scope.js

@@ -268,7 +268,7 @@ function load(path) {
 
 function getStatusFromDefinition(nockDef) {
   // Backward compatibility for when `status` was encoded as string in `reply`.
-  if (!_.isUndefined(nockDef.reply)) {
+  if (nockDef.reply !== undefined) {
     const parsedReply = parseInt(nockDef.reply, 10)
     if (isNaN(parsedReply)) {
       throw Error('`reply`, when present, must be a numeric string')
@@ -286,7 +286,7 @@ function getScopeFromDefinition(nockDef) {
   if (nockDef.port !== undefined) {
     //  Include `port` into scope if it doesn't exist.
     const options = url.parse(nockDef.scope)
-    if (_.isNull(options.port)) {
+    if (options.port === null) {
       return `${nockDef.scope}:${nockDef.port}`
     } else {
       if (parseInt(options.port) !== parseInt(nockDef.port)) {

tests/test_common.js

@@ -157,16 +157,16 @@ test('headersFieldNamesToLowerCase throws on conflicting keys', t => {
 
 test('headersFieldsArrayToLowerCase works on arrays', function(t) {
   t.deepEqual(
-    // Sort for comparison beause order doesn't matter.
+    // Sort for comparison because order doesn't matter.
     common.headersFieldsArrayToLowerCase(['HoSt', 'Content-typE']).sort(),
     ['content-type', 'host']
   )
   t.end()
 })
 
-test('headersFieldsArrayToLowerCase deduplicates arrays', function(t) {
+test('headersFieldsArrayToLowerCase de-duplicates arrays', function(t) {
   t.deepEqual(
-    // Sort for comparison beause order doesn't matter.
+    // Sort for comparison because order doesn't matter.
     common
       .headersFieldsArrayToLowerCase([
         'hosT',