diff --git a/until-each-right/docs/types/index.d.ts b/until-each-right/docs/types/index.d.ts
index 3b3b56a7..3c0a21e3 100644
--- a/until-each-right/docs/types/index.d.ts
+++ b/until-each-right/docs/types/index.d.ts
@@ -35,7 +35,7 @@ type NullaryPredicate = () => boolean;
 * @param value - collection value
 * @returns boolean indicating whether an element in a collection passes a test
 */
-type UnaryPredicate = ( value: any ) => boolean;
+type UnaryPredicate<T> = ( value: T ) => boolean;
 
 /**
 * Checks whether an element in a collection passes a test.
@@ -44,7 +44,7 @@ type UnaryPredicate = ( value: any ) => boolean;
 * @param index - collection index
 * @returns boolean indicating whether an element in a collection passes a test
 */
-type BinaryPredicate = ( value: any, index: number ) => boolean;
+type BinaryPredicate<T> = ( value: T, index: number ) => boolean;
 
 /**
 * Checks whether an element in a collection passes a test.
@@ -54,7 +54,7 @@ type BinaryPredicate = ( value: any, index: number ) => boolean;
 * @param collection - input collection
 * @returns boolean indicating whether an element in a collection passes a test
 */
-type TernaryPredicate = ( value: any, index: number, collection: Collection ) => boolean; // tslint-disable-line max-line-length
+type TernaryPredicate<T> = ( value: T, index: number, collection: Collection<T> ) => boolean; // tslint-disable-line max-line-length
 
 /**
 * Checks whether an element in a collection passes a test.
@@ -64,7 +64,7 @@ type TernaryPredicate = ( value: any, index: number, collection: Collection ) =>
 * @param collection - input collection
 * @returns boolean indicating whether an element in a collection passes a test
 */
-type Predicate = NullaryPredicate | UnaryPredicate | BinaryPredicate | TernaryPredicate; // tslint-disable-line max-line-length
+type Predicate<T> = NullaryPredicate | UnaryPredicate<T> | BinaryPredicate<T> | TernaryPredicate<T>; // tslint-disable-line max-line-length
 
 /**
 * Function invoked for each collection element until test condition is true.
@@ -76,7 +76,7 @@ type Nullary = () => void;
 *
 * @param value - collection value
 */
-type Unary = ( value: any ) => void;
+type Unary<T> = ( value: T ) => void;
 
 /**
 * Function invoked for each collection element until test condition is true.
@@ -84,7 +84,7 @@ type Unary = ( value: any ) => void;
 * @param value - collection value
 * @param index - collection index
 */
-type Binary = ( value: any, index: number ) => void;
+type Binary<T> = ( value: T, index: number ) => void;
 
 /**
 * Function invoked for each collection element until test condition is true.
@@ -93,7 +93,7 @@ type Binary = ( value: any, index: number ) => void;
 * @param index - collection index
 * @param collection - input collection
 */
-type Ternary = ( value: any, index: number, collection: Collection ) => void;
+type Ternary<T> = ( value: T, index: number, collection: Collection<T> ) => void; // tslint-disable-line max-line-length
 
 /**
 * Function invoked for each collection element until test condition is true.
@@ -102,7 +102,7 @@ type Ternary = ( value: any, index: number, collection: Collection ) => void;
 * @param index - collection index
 * @param collection - input collection
 */
-type Callback = Nullary | Unary | Binary | Ternary;
+type Callback<T> = Nullary | Unary<T> | Binary<T> | Ternary<T>;
 
 /**
 * Until a test condition is true, invokes a function once for each element in a collection, iterating from right to left.
@@ -136,7 +136,7 @@ type Callback = Nullary | Unary | Binary | Ternary;
 *
 * untilEachRight( arr, predicate, log );
 */
-declare function untilEachRight( collection: Collection, predicate: Predicate, fcn: Callback, thisArg?: any ): Collection; // tslint-disable-line max-line-length
+declare function untilEachRight<T = any>( collection: Collection<T>, predicate: Predicate<T>, fcn: Callback<T>, thisArg?: any ): Collection<T>; // tslint-disable-line max-line-length
 
 
 // EXPORTS //
diff --git a/until-each-right/docs/types/test.ts b/until-each-right/docs/types/test.ts
index 439ab101..5a11fbb9 100644
--- a/until-each-right/docs/types/test.ts
+++ b/until-each-right/docs/types/test.ts
@@ -18,54 +18,72 @@
 
 import untilEachRight = require( './index' );
 
-const log = ( v: any, index: number ): void => {
-	console.log( `${index}: ${v}` );
-};
+/**
+* Test function.
+*
+* @param v - value
+* @param index - index
+*/
+function fcn( v: number, index: number ): void {
+	if ( v !== v ) {
+		throw new Error( 'beep' );
+	}
+	if ( index !== index ) {
+		throw new Error( 'beep' );
+	}
+}
+
+/**
+* Test function.
+*
+* @param v - value
+* @returns result
+*/
+function isnan( v: number ): boolean {
+	return ( v !== v );
+}
 
-const isNotNaN = ( v: number ): boolean => {
-	return ( v === v );
-};
 
 // TESTS //
 
 // The function returns the input collection...
 {
-	untilEachRight( [ 0, 1, 1, NaN, 2 ], isNotNaN, log ); // $ExpectType Collection
-	untilEachRight( [ -1, 1, 2 ], isNotNaN, log, {} ); // $ExpectType Collection
+	untilEachRight( [ 0, 1, 1, NaN, 2 ], isnan, fcn ); // $ExpectType Collection<number>
+	untilEachRight( [ -1, 1, 2 ], isnan, fcn, {} ); // $ExpectType Collection<number>
 }
 
 // The compiler throws an error if the function is provided a first argument which is not a collection...
 {
-	untilEachRight( 2, isNotNaN, log ); // $ExpectError
-	untilEachRight( false, isNotNaN, log ); // $ExpectError
-	untilEachRight( true, isNotNaN, log ); // $ExpectError
-	untilEachRight( {}, isNotNaN, log ); // $ExpectError
+	untilEachRight( 2, isnan, fcn ); // $ExpectError
+	untilEachRight( false, isnan, fcn ); // $ExpectError
+	untilEachRight( true, isnan, fcn ); // $ExpectError
+	untilEachRight( {}, isnan, fcn ); // $ExpectError
 }
 
 // The compiler throws an error if the function is provided a second argument which is not a function...
 {
-	untilEachRight( [ 0, 1, 1, NaN, 2 ], 2, log ); // $ExpectError
-	untilEachRight( [ 0, 1, 1, NaN, 2 ], false, log ); // $ExpectError
-	untilEachRight( [ 0, 1, 1, NaN, 2 ], true, log ); // $ExpectError
-	untilEachRight( [ 0, 1, 1, NaN, 2 ], 'abc', log ); // $ExpectError
-	untilEachRight( [ 0, 1, 1, NaN, 2 ], {}, log ); // $ExpectError
-	untilEachRight( [ 0, 1, 1, NaN, 2 ], [], log ); // $ExpectError
+	untilEachRight( [ 0, 1, 1, NaN, 2 ], 2, fcn ); // $ExpectError
+	untilEachRight( [ 0, 1, 1, NaN, 2 ], false, fcn ); // $ExpectError
+	untilEachRight( [ 0, 1, 1, NaN, 2 ], true, fcn ); // $ExpectError
+	untilEachRight( [ 0, 1, 1, NaN, 2 ], 'abc', fcn ); // $ExpectError
+	untilEachRight( [ 0, 1, 1, NaN, 2 ], {}, fcn ); // $ExpectError
+	untilEachRight( [ 0, 1, 1, NaN, 2 ], [], fcn ); // $ExpectError
 }
 
 // The compiler throws an error if the function is provided a third argument which is not a function...
 {
-	untilEachRight( [ 0, 1, 1, NaN, 2 ], isNotNaN, 2 ); // $ExpectError
-	untilEachRight( [ 0, 1, 1, NaN, 2 ], isNotNaN, false ); // $ExpectError
-	untilEachRight( [ 0, 1, 1, NaN, 2 ], isNotNaN, true ); // $ExpectError
-	untilEachRight( [ 0, 1, 1, NaN, 2 ], isNotNaN, 'abc' ); // $ExpectError
-	untilEachRight( [ 0, 1, 1, NaN, 2 ], isNotNaN, {} ); // $ExpectError
-	untilEachRight( [ 0, 1, 1, NaN, 2 ], isNotNaN, [] ); // $ExpectError
+	untilEachRight( [ 0, 1, 1, NaN, 2 ], isnan, 2 ); // $ExpectError
+	untilEachRight( [ 0, 1, 1, NaN, 2 ], isnan, false ); // $ExpectError
+	untilEachRight( [ 0, 1, 1, NaN, 2 ], isnan, true ); // $ExpectError
+	untilEachRight( [ 0, 1, 1, NaN, 2 ], isnan, 'abc' ); // $ExpectError
+	untilEachRight( [ 0, 1, 1, NaN, 2 ], isnan, {} ); // $ExpectError
+	untilEachRight( [ 0, 1, 1, NaN, 2 ], isnan, [] ); // $ExpectError
 }
 
 // The compiler throws an error if the function is provided an invalid number of arguments...
 {
 	untilEachRight(); // $ExpectError
 	untilEachRight( [ 1, 2, 3 ] ); // $ExpectError
-	untilEachRight( [ 1, 2, 3 ], isNotNaN ); // $ExpectError
-	untilEachRight( [ 1, 2, 3 ], isNotNaN, log, {}, 3 ); // $ExpectError
+	untilEachRight( [ 1, 2, 3 ], isnan ); // $ExpectError
+	untilEachRight( [ 1, 2, 3 ], isnan, fcn, {}, 3 ); // $ExpectError
 }
diff --git a/until-each/docs/types/index.d.ts b/until-each/docs/types/index.d.ts
index f0c79626..ed42fa5b 100644
--- a/until-each/docs/types/index.d.ts
+++ b/until-each/docs/types/index.d.ts
@@ -35,7 +35,7 @@ type NullaryPredicate = () => boolean;
 * @param value - collection value
 * @returns boolean indicating whether an element in a collection passes a test
 */
-type UnaryPredicate = ( value: any ) => boolean;
+type UnaryPredicate<T> = ( value: T ) => boolean;
 
 /**
 * Checks whether an element in a collection passes a test.
@@ -44,7 +44,7 @@ type UnaryPredicate = ( value: any ) => boolean;
 * @param index - collection index
 * @returns boolean indicating whether an element in a collection passes a test
 */
-type BinaryPredicate = ( value: any, index: number ) => boolean;
+type BinaryPredicate<T> = ( value: T, index: number ) => boolean;
 
 /**
 * Checks whether an element in a collection passes a test.
@@ -54,7 +54,7 @@ type BinaryPredicate = ( value: any, index: number ) => boolean;
 * @param collection - input collection
 * @returns boolean indicating whether an element in a collection passes a test
 */
-type TernaryPredicate = ( value: any, index: number, collection: Collection ) => boolean; // tslint-disable-line max-line-length
+type TernaryPredicate<T> = ( value: T, index: number, collection: Collection<T> ) => boolean; // tslint-disable-line max-line-length
 
 /**
 * Checks whether an element in a collection passes a test.
@@ -64,7 +64,7 @@ type TernaryPredicate = ( value: any, index: number, collection: Collection ) =>
 * @param collection - input collection
 * @returns boolean indicating whether an element in a collection passes a test
 */
-type Predicate = NullaryPredicate | UnaryPredicate | BinaryPredicate | TernaryPredicate; // tslint-disable-line max-line-length
+type Predicate<T> = NullaryPredicate | UnaryPredicate<T> | BinaryPredicate<T> | TernaryPredicate<T>; // tslint-disable-line max-line-length
 
 /**
 * Function invoked for each collection element until test condition is true.
@@ -76,7 +76,7 @@ type Nullary = () => void;
 *
 * @param value - collection value
 */
-type Unary = ( value: any ) => void;
+type Unary<T> = ( value: T ) => void;
 
 /**
 * Function invoked for each collection element until test condition is true.
@@ -84,7 +84,7 @@ type Unary = ( value: any ) => void;
 * @param value - collection value
 * @param index - collection index
 */
-type Binary = ( value: any, index: number ) => void;
+type Binary<T> = ( value: T, index: number ) => void;
 
 /**
 * Function invoked for each collection element until test condition is true.
@@ -93,7 +93,7 @@ type Binary = ( value: any, index: number ) => void;
 * @param index - collection index
 * @param collection - input collection
 */
-type Ternary = ( value: any, index: number, collection: Collection ) => void;
+type Ternary<T> = ( value: T, index: number, collection: Collection<T> ) => void; // tslint-disable-line max-line-length
 
 /**
 * Function invoked for each collection element until test condition is true.
@@ -102,7 +102,7 @@ type Ternary = ( value: any, index: number, collection: Collection ) => void;
 * @param index - collection index
 * @param collection - input collection
 */
-type Callback = Nullary | Unary | Binary | Ternary;
+type Callback<T> = Nullary | Unary<T> | Binary<T> | Ternary<T>;
 
 /**
 * Until a test condition is true, invokes a function once for each element in a collection.
@@ -134,7 +134,7 @@ type Callback = Nullary | Unary | Binary | Ternary;
 *
 * untilEach( arr, predicate, log );
 */
-declare function untilEach( collection: Collection, predicate: Predicate, fcn: Callback, thisArg?: any ): Collection; // tslint-disable-line max-line-length
+declare function untilEach<T = any>( collection: Collection<T>, predicate: Predicate<T>, fcn: Callback<T>, thisArg?: any ): Collection<T>; // tslint-disable-line max-line-length
 
 
 // EXPORTS //
diff --git a/until-each/docs/types/test.ts b/until-each/docs/types/test.ts
index 753d0bb7..48332835 100644
--- a/until-each/docs/types/test.ts
+++ b/until-each/docs/types/test.ts
@@ -18,54 +18,72 @@
 
 import untilEach = require( './index' );
 
-const log = ( v: any, index: number ): void => {
-	console.log( `${index}: ${v}` );
-};
+/**
+* Test function.
+*
+* @param v - value
+* @param index - index
+*/
+function fcn( v: number, index: number ): void {
+	if ( v !== v ) {
+		throw new Error( 'beep' );
+	}
+	if ( index !== index ) {
+		throw new Error( 'beep' );
+	}
+}
+
+/**
+* Test function.
+*
+* @param v - value
+* @returns result
+*/
+function isnan( v: number ): boolean {
+	return ( v !== v );
+}
 
-const isNotNaN = ( v: number ): boolean => {
-	return ( v === v );
-};
 
 // TESTS //
 
 // The function returns the input collection...
 {
-	untilEach( [ 0, 1, 1, NaN, 2 ], isNotNaN, log ); // $ExpectType Collection
-	untilEach( [ -1, 1, 2 ], isNotNaN, log, {} ); // $ExpectType Collection
+	untilEach( [ 0, 1, 1, NaN, 2 ], isnan, fcn ); // $ExpectType Collection<number>
+	untilEach( [ -1, 1, 2 ], isnan, fcn, {} ); // $ExpectType Collection<number>
 }
 
 // The compiler throws an error if the function is provided a first argument which is not a collection...
 {
-	untilEach( 2, isNotNaN, log ); // $ExpectError
-	untilEach( false, isNotNaN, log ); // $ExpectError
-	untilEach( true, isNotNaN, log ); // $ExpectError
-	untilEach( {}, isNotNaN, log ); // $ExpectError
+	untilEach( 2, isnan, fcn ); // $ExpectError
+	untilEach( false, isnan, fcn ); // $ExpectError
+	untilEach( true, isnan, fcn ); // $ExpectError
+	untilEach( {}, isnan, fcn ); // $ExpectError
 }
 
 // The compiler throws an error if the function is provided a second argument which is not a function...
 {
-	untilEach( [ 0, 1, 1, NaN, 2 ], 2, log ); // $ExpectError
-	untilEach( [ 0, 1, 1, NaN, 2 ], false, log ); // $ExpectError
-	untilEach( [ 0, 1, 1, NaN, 2 ], true, log ); // $ExpectError
-	untilEach( [ 0, 1, 1, NaN, 2 ], 'abc', log ); // $ExpectError
-	untilEach( [ 0, 1, 1, NaN, 2 ], {}, log ); // $ExpectError
-	untilEach( [ 0, 1, 1, NaN, 2 ], [], log ); // $ExpectError
+	untilEach( [ 0, 1, 1, NaN, 2 ], 2, fcn ); // $ExpectError
+	untilEach( [ 0, 1, 1, NaN, 2 ], false, fcn ); // $ExpectError
+	untilEach( [ 0, 1, 1, NaN, 2 ], true, fcn ); // $ExpectError
+	untilEach( [ 0, 1, 1, NaN, 2 ], 'abc', fcn ); // $ExpectError
+	untilEach( [ 0, 1, 1, NaN, 2 ], {}, fcn ); // $ExpectError
+	untilEach( [ 0, 1, 1, NaN, 2 ], [], fcn ); // $ExpectError
 }
 
 // The compiler throws an error if the function is provided a third argument which is not a function...
 {
-	untilEach( [ 0, 1, 1, NaN, 2 ], isNotNaN, 2 ); // $ExpectError
-	untilEach( [ 0, 1, 1, NaN, 2 ], isNotNaN, false ); // $ExpectError
-	untilEach( [ 0, 1, 1, NaN, 2 ], isNotNaN, true ); // $ExpectError
-	untilEach( [ 0, 1, 1, NaN, 2 ], isNotNaN, 'abc' ); // $ExpectError
-	untilEach( [ 0, 1, 1, NaN, 2 ], isNotNaN, {} ); // $ExpectError
-	untilEach( [ 0, 1, 1, NaN, 2 ], isNotNaN, [] ); // $ExpectError
+	untilEach( [ 0, 1, 1, NaN, 2 ], isnan, 2 ); // $ExpectError
+	untilEach( [ 0, 1, 1, NaN, 2 ], isnan, false ); // $ExpectError
+	untilEach( [ 0, 1, 1, NaN, 2 ], isnan, true ); // $ExpectError
+	untilEach( [ 0, 1, 1, NaN, 2 ], isnan, 'abc' ); // $ExpectError
+	untilEach( [ 0, 1, 1, NaN, 2 ], isnan, {} ); // $ExpectError
+	untilEach( [ 0, 1, 1, NaN, 2 ], isnan, [] ); // $ExpectError
 }
 
 // The compiler throws an error if the function is provided an invalid number of arguments...
 {
 	untilEach(); // $ExpectError
 	untilEach( [ 1, 2, 3 ] ); // $ExpectError
-	untilEach( [ 1, 2, 3 ], isNotNaN ); // $ExpectError
-	untilEach( [ 1, 2, 3 ], isNotNaN, log, {}, 3 ); // $ExpectError
+	untilEach( [ 1, 2, 3 ], isnan ); // $ExpectError
+	untilEach( [ 1, 2, 3 ], isnan, fcn, {}, 3 ); // $ExpectError
 }
diff --git a/while-each-right/docs/types/test.ts b/while-each-right/docs/types/test.ts
index fd6942bd..f2a59033 100644
--- a/while-each-right/docs/types/test.ts
+++ b/while-each-right/docs/types/test.ts
@@ -18,18 +18,31 @@
 
 import whileEachRight = require( './index' );
 
-const fcn = ( v: number, index: number ): void => {
+/**
+* Test function.
+*
+* @param v - value
+* @param index - index
+*/
+function fcn( v: number, index: number ): void {
 	if ( v !== v ) {
 		throw new Error( 'beep' );
 	}
 	if ( index !== index ) {
 		throw new Error( 'beep' );
 	}
-};
+}
 
-const isnan = ( v: number ): boolean => {
+/**
+* Test function.
+*
+* @param v - value
+* @returns result
+*/
+function isnan( v: number ): boolean {
 	return ( v !== v );
-};
+}
+
 
 // TESTS //
 
diff --git a/while-each/docs/types/index.d.ts b/while-each/docs/types/index.d.ts
index 6ad92152..d6621835 100644
--- a/while-each/docs/types/index.d.ts
+++ b/while-each/docs/types/index.d.ts
@@ -16,7 +16,7 @@
 * limitations under the License.
 */
 
-// TypeScript Version: 2.0
+// TypeScript Version: 4.1
 
 /// <reference types="@stdlib/types"/>
 
@@ -35,7 +35,7 @@ type NullaryPredicate = () => boolean;
 * @param value - collection value
 * @returns boolean indicating whether an element in a collection passes a test
 */
-type UnaryPredicate = ( value: any ) => boolean;
+type UnaryPredicate<T> = ( value: T ) => boolean;
 
 /**
 * Checks whether an element in a collection passes a test.
@@ -44,7 +44,7 @@ type UnaryPredicate = ( value: any ) => boolean;
 * @param index - collection index
 * @returns boolean indicating whether an element in a collection passes a test
 */
-type BinaryPredicate = ( value: any, index: number ) => boolean;
+type BinaryPredicate<T> = ( value: T, index: number ) => boolean;
 
 /**
 * Checks whether an element in a collection passes a test.
@@ -54,7 +54,7 @@ type BinaryPredicate = ( value: any, index: number ) => boolean;
 * @param collection - input collection
 * @returns boolean indicating whether an element in a collection passes a test
 */
-type TernaryPredicate = ( value: any, index: number, collection: Collection ) => boolean; // tslint-disable-line max-line-length
+type TernaryPredicate<T> = ( value: T, index: number, collection: Collection<T> ) => boolean; // tslint-disable-line max-line-length
 
 /**
 * Checks whether an element in a collection passes a test.
@@ -64,7 +64,7 @@ type TernaryPredicate = ( value: any, index: number, collection: Collection ) =>
 * @param collection - input collection
 * @returns boolean indicating whether an element in a collection passes a test
 */
-type Predicate = NullaryPredicate | UnaryPredicate | BinaryPredicate | TernaryPredicate; // tslint-disable-line max-line-length
+type Predicate<T> = NullaryPredicate | UnaryPredicate<T> | BinaryPredicate<T> | TernaryPredicate<T>; // tslint-disable-line max-line-length
 
 /**
 * Function invoked for each collection element passing a test.
@@ -76,7 +76,7 @@ type Nullary = () => void;
 *
 * @param value - collection value
 */
-type Unary = ( value: any ) => void;
+type Unary<T> = ( value: T ) => void;
 
 /**
 * Function invoked for each collection element passing a test.
@@ -84,7 +84,7 @@ type Unary = ( value: any ) => void;
 * @param value - collection value
 * @param index - collection index
 */
-type Binary = ( value: any, index: number ) => void;
+type Binary<T> = ( value: T, index: number ) => void;
 
 /**
 * Function invoked for each collection element passing a test.
@@ -93,7 +93,7 @@ type Binary = ( value: any, index: number ) => void;
 * @param index - collection index
 * @param collection - input collection
 */
-type Ternary = ( value: any, index: number, collection: Collection ) => void;
+type Ternary<T> = ( value: T, index: number, collection: Collection<T> ) => void; // tslint-disable-line max-line-length
 
 /**
 * Function invoked for each collection element passing a test.
@@ -102,7 +102,7 @@ type Ternary = ( value: any, index: number, collection: Collection ) => void;
 * @param index - collection index
 * @param collection - input collection
 */
-type Callback = Nullary | Unary | Binary | Ternary;
+type Callback<T> = Nullary | Unary<T> | Binary<T> | Ternary<T>;
 
 /**
 * While a test condition is true, invokes a function once for each element in a collection.
@@ -134,7 +134,7 @@ type Callback = Nullary | Unary | Binary | Ternary;
 *
 * whileEach( arr, predicate, log );
 */
-declare function whileEach( collection: Collection, predicate: Predicate, fcn: Callback, thisArg?: any ): Collection; // tslint-disable-line max-line-length
+declare function whileEach<T = any>( collection: Collection<T>, predicate: Predicate<T>, fcn: Callback<T>, thisArg?: any ): Collection<T>; // tslint-disable-line max-line-length
 
 
 // EXPORTS //
diff --git a/while-each/docs/types/test.ts b/while-each/docs/types/test.ts
index 5fda235f..d97f834b 100644
--- a/while-each/docs/types/test.ts
+++ b/while-each/docs/types/test.ts
@@ -18,54 +18,72 @@
 
 import whileEach = require( './index' );
 
-const log = ( v: any, index: number ): void => {
-	console.log( `${index}: ${v}` );
-};
+/**
+* Test function.
+*
+* @param v - value
+* @param index - index
+*/
+function fcn( v: number, index: number ): void {
+	if ( v !== v ) {
+		throw new Error( 'beep' );
+	}
+	if ( index !== index ) {
+		throw new Error( 'beep' );
+	}
+}
+
+/**
+* Test function.
+*
+* @param v - value
+* @returns result
+*/
+function isnan( v: number ): boolean {
+	return ( v !== v );
+}
 
-const isNotNaN = ( v: number ): boolean => {
-	return ( v === v );
-};
 
 // TESTS //
 
 // The function returns the input collection...
 {
-	whileEach( [ 0, 1, 1, NaN, 2 ], isNotNaN, log ); // $ExpectType Collection
-	whileEach( [ -1, 1, 2 ], isNotNaN, log, {} ); // $ExpectType Collection
+	whileEach( [ 0, 1, 1, NaN, 2 ], isnan, fcn ); // $ExpectType Collection<number>
+	whileEach( [ -1, 1, 2 ], isnan, fcn, {} ); // $ExpectType Collection<number>
 }
 
 // The compiler throws an error if the function is provided a first argument which is not a collection...
 {
-	whileEach( 2, isNotNaN, log ); // $ExpectError
-	whileEach( false, isNotNaN, log ); // $ExpectError
-	whileEach( true, isNotNaN, log ); // $ExpectError
-	whileEach( {}, isNotNaN, log ); // $ExpectError
+	whileEach( 2, isnan, fcn ); // $ExpectError
+	whileEach( false, isnan, fcn ); // $ExpectError
+	whileEach( true, isnan, fcn ); // $ExpectError
+	whileEach( {}, isnan, fcn ); // $ExpectError
 }
 
 // The compiler throws an error if the function is provided a second argument which is not a function...
 {
-	whileEach( [ 0, 1, 1, NaN, 2 ], 2, log ); // $ExpectError
-	whileEach( [ 0, 1, 1, NaN, 2 ], false, log ); // $ExpectError
-	whileEach( [ 0, 1, 1, NaN, 2 ], true, log ); // $ExpectError
-	whileEach( [ 0, 1, 1, NaN, 2 ], 'abc', log ); // $ExpectError
-	whileEach( [ 0, 1, 1, NaN, 2 ], {}, log ); // $ExpectError
-	whileEach( [ 0, 1, 1, NaN, 2 ], [], log ); // $ExpectError
+	whileEach( [ 0, 1, 1, NaN, 2 ], 2, fcn ); // $ExpectError
+	whileEach( [ 0, 1, 1, NaN, 2 ], false, fcn ); // $ExpectError
+	whileEach( [ 0, 1, 1, NaN, 2 ], true, fcn ); // $ExpectError
+	whileEach( [ 0, 1, 1, NaN, 2 ], 'abc', fcn ); // $ExpectError
+	whileEach( [ 0, 1, 1, NaN, 2 ], {}, fcn ); // $ExpectError
+	whileEach( [ 0, 1, 1, NaN, 2 ], [], fcn ); // $ExpectError
 }
 
 // The compiler throws an error if the function is provided a third argument which is not a function...
 {
-	whileEach( [ 0, 1, 1, NaN, 2 ], isNotNaN, 2 ); // $ExpectError
-	whileEach( [ 0, 1, 1, NaN, 2 ], isNotNaN, false ); // $ExpectError
-	whileEach( [ 0, 1, 1, NaN, 2 ], isNotNaN, true ); // $ExpectError
-	whileEach( [ 0, 1, 1, NaN, 2 ], isNotNaN, 'abc' ); // $ExpectError
-	whileEach( [ 0, 1, 1, NaN, 2 ], isNotNaN, {} ); // $ExpectError
-	whileEach( [ 0, 1, 1, NaN, 2 ], isNotNaN, [] ); // $ExpectError
+	whileEach( [ 0, 1, 1, NaN, 2 ], isnan, 2 ); // $ExpectError
+	whileEach( [ 0, 1, 1, NaN, 2 ], isnan, false ); // $ExpectError
+	whileEach( [ 0, 1, 1, NaN, 2 ], isnan, true ); // $ExpectError
+	whileEach( [ 0, 1, 1, NaN, 2 ], isnan, 'abc' ); // $ExpectError
+	whileEach( [ 0, 1, 1, NaN, 2 ], isnan, {} ); // $ExpectError
+	whileEach( [ 0, 1, 1, NaN, 2 ], isnan, [] ); // $ExpectError
 }
 
 // The compiler throws an error if the function is provided an invalid number of arguments...
 {
 	whileEach(); // $ExpectError
 	whileEach( [ 1, 2, 3 ] ); // $ExpectError
-	whileEach( [ 1, 2, 3 ], isNotNaN ); // $ExpectError
-	whileEach( [ 1, 2, 3 ], isNotNaN, log, {}, 3 ); // $ExpectError
+	whileEach( [ 1, 2, 3 ], isnan ); // $ExpectError
+	whileEach( [ 1, 2, 3 ], isnan, fcn, {}, 3 ); // $ExpectError
 }