Move argument length requirement checks to a shared function to dedupe code

src/_lib/getUTCDayOfYear/index.js

@@ -1,15 +1,12 @@
 import toDate from '../../toDate/index.js'
+import requiredArgs from '../requiredArgs/index.js'
 
 var MILLISECONDS_IN_DAY = 86400000
 
 // This function will be a part of public API when UTC function will be implemented.
 // See issue: https://github.com/date-fns/date-fns/issues/376
 export default function getUTCDayOfYear(dirtyDate) {
-  if (arguments.length < 1) {
-    throw new TypeError(
-      '1 argument required, but only ' + arguments.length + ' present'
-    )
-  }
+  requiredArgs(1, arguments)
 
   var date = toDate(dirtyDate)
   var timestamp = date.getTime()

src/_lib/getUTCISOWeek/index.js

@@ -1,17 +1,14 @@
 import toDate from '../../toDate/index.js'
 import startOfUTCISOWeek from '../startOfUTCISOWeek/index.js'
 import startOfUTCISOWeekYear from '../startOfUTCISOWeekYear/index.js'
+import requiredArgs from '../requiredArgs/index.js'
 
 var MILLISECONDS_IN_WEEK = 604800000
 
 // This function will be a part of public API when UTC function will be implemented.
 // See issue: https://github.com/date-fns/date-fns/issues/376
 export default function getUTCISOWeek(dirtyDate) {
-  if (arguments.length < 1) {
-    throw new TypeError(
-      '1 argument required, but only ' + arguments.length + ' present'
-    )
-  }
+  requiredArgs(1, arguments)
 
   var date = toDate(dirtyDate)
   var diff =

src/_lib/getUTCISOWeekYear/index.js

@@ -1,14 +1,11 @@
 import toDate from '../../toDate/index.js'
 import startOfUTCISOWeek from '../startOfUTCISOWeek/index.js'
+import requiredArgs from '../requiredArgs/index.js'
 
 // This function will be a part of public API when UTC function will be implemented.
 // See issue: https://github.com/date-fns/date-fns/issues/376
 export default function getUTCISOWeekYear(dirtyDate) {
-  if (arguments.length < 1) {
-    throw new TypeError(
-      '1 argument required, but only ' + arguments.length + ' present'
-    )
-  }
+  requiredArgs(1, arguments)
 
   var date = toDate(dirtyDate)
   var year = date.getUTCFullYear()

src/_lib/getUTCWeek/index.js

@@ -1,17 +1,14 @@
 import toDate from '../../toDate/index.js'
 import startOfUTCWeek from '../startOfUTCWeek/index.js'
 import startOfUTCWeekYear from '../startOfUTCWeekYear/index.js'
+import requiredArgs from '../requiredArgs/index.js'
 
 var MILLISECONDS_IN_WEEK = 604800000
 
 // This function will be a part of public API when UTC function will be implemented.
 // See issue: https://github.com/date-fns/date-fns/issues/376
 export default function getUTCWeek(dirtyDate, options) {
-  if (arguments.length < 1) {
-    throw new TypeError(
-      '1 argument required, but only ' + arguments.length + ' present'
-    )
-  }
+  requiredArgs(1, arguments)
 
   var date = toDate(dirtyDate)
   var diff =

src/_lib/getUTCWeekYear/index.js

@@ -1,13 +1,12 @@
 import toInteger from '../toInteger/index.js'
 import toDate from '../../toDate/index.js'
 import startOfUTCWeek from '../startOfUTCWeek/index.js'
+import requiredArgs from '../requiredArgs/index.js'
 
 // This function will be a part of public API when UTC function will be implemented.
 // See issue: https://github.com/date-fns/date-fns/issues/376
-export default function getUTCWeekYear (dirtyDate, dirtyOptions) {
-  if (arguments.length < 1) {
-    throw new TypeError('1 argument required, but only ' + arguments.length + ' present')
-  }
+export default function getUTCWeekYear(dirtyDate, dirtyOptions) {
+  requiredArgs(1, arguments)
 
   var date = toDate(dirtyDate, dirtyOptions)
   var year = date.getUTCFullYear()

src/_lib/isSameUTCWeek/index.js

@@ -1,13 +1,10 @@
 import startOfUTCWeek from '../startOfUTCWeek/index.js'
+import requiredArgs from '../requiredArgs/index.js'
 
 // This function will be a part of public API when UTC function will be implemented.
 // See issue: https://github.com/date-fns/date-fns/issues/376
 export default function isSameUTCWeek(dirtyDateLeft, dirtyDateRight, options) {
-  if (arguments.length < 2) {
-    throw new TypeError(
-      '2 argument required, but only ' + arguments.length + ' present'
-    )
-  }
+  requiredArgs(2, arguments)
 
   var dateLeftStartOfWeek = startOfUTCWeek(dirtyDateLeft, options)
   var dateRightStartOfWeek = startOfUTCWeek(dirtyDateRight, options)

src/_lib/requiredArgs/index.js

@@ -0,0 +1,9 @@
+export default function requiredArgs(required, args) {
+  if (args.length < required) {
+    throw new TypeError(
+      required + ' argument' + required > 1
+        ? 's'
+        : '' + ' required, but only ' + args.length + ' present'
+    )
+  }
+}

src/_lib/setUTCDay/index.js

@@ -1,14 +1,11 @@
 import toInteger from '../toInteger/index.js'
 import toDate from '../../toDate/index.js'
+import requiredArgs from '../requiredArgs/index.js'
 
 // This function will be a part of public API when UTC function will be implemented.
 // See issue: https://github.com/date-fns/date-fns/issues/376
 export default function setUTCDay(dirtyDate, dirtyDay, dirtyOptions) {
-  if (arguments.length < 2) {
-    throw new TypeError(
-      '2 arguments required, but only ' + arguments.length + ' present'
-    )
-  }
+  requiredArgs(2, arguments)
 
   var options = dirtyOptions || {}
   var locale = options.locale

src/_lib/setUTCISODay/index.js

@@ -1,14 +1,11 @@
 import toInteger from '../toInteger/index.js'
 import toDate from '../../toDate/index.js'
+import requiredArgs from '../requiredArgs/index.js'
 
 // This function will be a part of public API when UTC function will be implemented.
 // See issue: https://github.com/date-fns/date-fns/issues/376
 export default function setUTCISODay(dirtyDate, dirtyDay) {
-  if (arguments.length < 2) {
-    throw new TypeError(
-      '2 arguments required, but only ' + arguments.length + ' present'
-    )
-  }
+  requiredArgs(2, arguments)
 
   var day = toInteger(dirtyDay)
 

src/_lib/setUTCISOWeek/index.js

@@ -1,15 +1,12 @@
 import toInteger from '../toInteger/index.js'
 import toDate from '../../toDate/index.js'
 import getUTCISOWeek from '../getUTCISOWeek/index.js'
+import requiredArgs from '../requiredArgs/index.js'
 
 // This function will be a part of public API when UTC function will be implemented.
 // See issue: https://github.com/date-fns/date-fns/issues/376
 export default function setUTCISOWeek(dirtyDate, dirtyISOWeek) {
-  if (arguments.length < 2) {
-    throw new TypeError(
-      '2 arguments required, but only ' + arguments.length + ' present'
-    )
-  }
+  requiredArgs(2, arguments)
 
   var date = toDate(dirtyDate)
   var isoWeek = toInteger(dirtyISOWeek)

src/_lib/setUTCWeek/index.js

@@ -1,15 +1,12 @@
 import toInteger from '../toInteger/index.js'
 import toDate from '../../toDate/index.js'
 import getUTCWeek from '../getUTCWeek/index.js'
+import requiredArgs from '../requiredArgs/index.js'
 
 // This function will be a part of public API when UTC function will be implemented.
 // See issue: https://github.com/date-fns/date-fns/issues/376
 export default function setUTCWeek(dirtyDate, dirtyWeek, options) {
-  if (arguments.length < 2) {
-    throw new TypeError(
-      '2 arguments required, but only ' + arguments.length + ' present'
-    )
-  }
+  requiredArgs(2, arguments)
 
   var date = toDate(dirtyDate)
   var week = toInteger(dirtyWeek)

src/_lib/startOfUTCISOWeek/index.js

@@ -1,13 +1,10 @@
 import toDate from '../../toDate/index.js'
+import requiredArgs from '../requiredArgs/index.js'
 
 // This function will be a part of public API when UTC function will be implemented.
 // See issue: https://github.com/date-fns/date-fns/issues/376
 export default function startOfUTCISOWeek(dirtyDate) {
-  if (arguments.length < 1) {
-    throw new TypeError(
-      '1 argument required, but only ' + arguments.length + ' present'
-    )
-  }
+  requiredArgs(1, arguments)
 
   var weekStartsOn = 1
 

src/_lib/startOfUTCISOWeekYear/index.js

@@ -1,14 +1,11 @@
 import getUTCISOWeekYear from '../getUTCISOWeekYear/index.js'
 import startOfUTCISOWeek from '../startOfUTCISOWeek/index.js'
+import requiredArgs from '../requiredArgs/index.js'
 
 // This function will be a part of public API when UTC function will be implemented.
 // See issue: https://github.com/date-fns/date-fns/issues/376
 export default function startOfUTCISOWeekYear(dirtyDate) {
-  if (arguments.length < 1) {
-    throw new TypeError(
-      '1 argument required, but only ' + arguments.length + ' present'
-    )
-  }
+  requiredArgs(1, arguments)
 
   var year = getUTCISOWeekYear(dirtyDate)
   var fourthOfJanuary = new Date(0)

src/_lib/startOfUTCWeek/index.js

@@ -1,14 +1,11 @@
 import toInteger from '../toInteger/index.js'
 import toDate from '../../toDate/index.js'
+import requiredArgs from '../requiredArgs/index.js'
 
 // This function will be a part of public API when UTC function will be implemented.
 // See issue: https://github.com/date-fns/date-fns/issues/376
 export default function startOfUTCWeek(dirtyDate, dirtyOptions) {
-  if (arguments.length < 1) {
-    throw new TypeError(
-      '1 argument required, but only ' + arguments.length + ' present'
-    )
-  }
+  requiredArgs(1, arguments)
 
   var options = dirtyOptions || {}
   var locale = options.locale

src/_lib/startOfUTCWeekYear/index.js

@@ -1,13 +1,12 @@
 import toInteger from '../toInteger/index.js'
 import getUTCWeekYear from '../getUTCWeekYear/index.js'
 import startOfUTCWeek from '../startOfUTCWeek/index.js'
+import requiredArgs from '../requiredArgs/index.js'
 
 // This function will be a part of public API when UTC function will be implemented.
 // See issue: https://github.com/date-fns/date-fns/issues/376
-export default function startOfUTCWeekYear (dirtyDate, dirtyOptions) {
-  if (arguments.length < 1) {
-    throw new TypeError('1 argument required, but only ' + arguments.length + ' present')
-  }
+export default function startOfUTCWeekYear(dirtyDate, dirtyOptions) {
+  requiredArgs(1, arguments)
 
   var options = dirtyOptions || {}
   var locale = options.locale

src/addBusinessDays/index.js

@@ -1,6 +1,7 @@
 import isWeekend from '../isWeekend/index.js'
 import toDate from '../toDate/index.js'
 import toInteger from '../_lib/toInteger/index.js'
+import requiredArgs from '../_lib/requiredArgs/index.js'
 
 /**
  * @name addBusinessDays
@@ -21,11 +22,7 @@ import toInteger from '../_lib/toInteger/index.js'
  * //=> Mon Sep 15 2014 00:00:00 (skipped weekend days)
  */
 export default function addBusinessDays(dirtyDate, dirtyAmount) {
-  if (arguments.length < 2) {
-    throw new TypeError(
-      '2 arguments required, but only ' + arguments.length + ' present'
-    )
-  }
+  requiredArgs(2, arguments)
 
   var date = toDate(dirtyDate)
   var amount = toInteger(dirtyAmount)

src/addDays/index.js

@@ -1,5 +1,6 @@
 import toInteger from '../_lib/toInteger/index.js'
 import toDate from '../toDate/index.js'
+import requiredArgs from '../_lib/requiredArgs/index.js'
 
 /**
  * @name addDays
@@ -24,11 +25,7 @@ import toDate from '../toDate/index.js'
  * //=> Thu Sep 11 2014 00:00:00
  */
 export default function addDays(dirtyDate, dirtyAmount) {
-  if (arguments.length < 2) {
-    throw new TypeError(
-      '2 arguments required, but only ' + arguments.length + ' present'
-    )
-  }
+  requiredArgs(2, arguments)
 
   var date = toDate(dirtyDate)
   var amount = toInteger(dirtyAmount)

src/addHours/index.js

@@ -1,5 +1,6 @@
 import toInteger from '../_lib/toInteger/index.js'
 import addMilliseconds from '../addMilliseconds/index.js'
+import requiredArgs from '../_lib/requiredArgs/index.js'
 
 var MILLISECONDS_IN_HOUR = 3600000
 
@@ -26,11 +27,7 @@ var MILLISECONDS_IN_HOUR = 3600000
  * //=> Fri Jul 11 2014 01:00:00
  */
 export default function addHours(dirtyDate, dirtyAmount) {
-  if (arguments.length < 2) {
-    throw new TypeError(
-      '2 arguments required, but only ' + arguments.length + ' present'
-    )
-  }
+  requiredArgs(2, arguments)
 
   var amount = toInteger(dirtyAmount)
   return addMilliseconds(dirtyDate, amount * MILLISECONDS_IN_HOUR)

src/addISOWeekYears/index.js

@@ -1,6 +1,7 @@
 import toInteger from '../_lib/toInteger/index.js'
 import getISOWeekYear from '../getISOWeekYear/index.js'
 import setISOWeekYear from '../setISOWeekYear/index.js'
+import requiredArgs from '../_lib/requiredArgs/index.js'
 
 /**
  * @name addISOWeekYears
@@ -32,11 +33,7 @@ import setISOWeekYear from '../setISOWeekYear/index.js'
  * //=> Fri Jun 26 2015 00:00:00
  */
 export default function addISOWeekYears(dirtyDate, dirtyAmount) {
-  if (arguments.length < 2) {
-    throw new TypeError(
-      '2 arguments required, but only ' + arguments.length + ' present'
-    )
-  }
+  requiredArgs(2, arguments)
 
   var amount = toInteger(dirtyAmount)
   return setISOWeekYear(dirtyDate, getISOWeekYear(dirtyDate) + amount)

src/addMilliseconds/index.js

@@ -1,5 +1,6 @@
 import toInteger from '../_lib/toInteger/index.js'
 import toDate from '../toDate/index.js'
+import requiredArgs from '../_lib/requiredArgs/index.js'
 
 /**
  * @name addMilliseconds
@@ -24,11 +25,7 @@ import toDate from '../toDate/index.js'
  * //=> Thu Jul 10 2014 12:45:30.750
  */
 export default function addMilliseconds(dirtyDate, dirtyAmount) {
-  if (arguments.length < 2) {
-    throw new TypeError(
-      '2 arguments required, but only ' + arguments.length + ' present'
-    )
-  }
+  requiredArgs(2, arguments)
 
   var timestamp = toDate(dirtyDate).getTime()
   var amount = toInteger(dirtyAmount)

src/addMinutes/index.js

@@ -1,5 +1,6 @@
 import toInteger from '../_lib/toInteger/index.js'
 import addMilliseconds from '../addMilliseconds/index.js'
+import requiredArgs from '../_lib/requiredArgs/index.js'
 
 var MILLISECONDS_IN_MINUTE = 60000
 
@@ -26,11 +27,7 @@ var MILLISECONDS_IN_MINUTE = 60000
  * //=> Thu Jul 10 2014 12:30:00
  */
 export default function addMinutes(dirtyDate, dirtyAmount) {
-  if (arguments.length < 2) {
-    throw new TypeError(
-      '2 arguments required, but only ' + arguments.length + ' present'
-    )
-  }
+  requiredArgs(2, arguments)
 
   var amount = toInteger(dirtyAmount)
   return addMilliseconds(dirtyDate, amount * MILLISECONDS_IN_MINUTE)

src/addMonths/index.js

@@ -1,6 +1,7 @@
 import toInteger from '../_lib/toInteger/index.js'
 import toDate from '../toDate/index.js'
 import getDaysInMonth from '../getDaysInMonth/index.js'
+import requiredArgs from '../_lib/requiredArgs/index.js'
 
 /**
  * @name addMonths
@@ -25,11 +26,7 @@ import getDaysInMonth from '../getDaysInMonth/index.js'
  * //=> Sun Feb 01 2015 00:00:00
  */
 export default function addMonths(dirtyDate, dirtyAmount) {
-  if (arguments.length < 2) {
-    throw new TypeError(
-      '2 arguments required, but only ' + arguments.length + ' present'
-    )
-  }
+  requiredArgs(2, arguments)
 
   var date = toDate(dirtyDate)
   var amount = toInteger(dirtyAmount)