refactor: update docs and tests

---
type: pre_commit_static_analysis_report
description: Results of running static analysis checks when committing changes.
report:
  - task: lint_filenames
    status: passed
  - task: lint_editorconfig
    status: passed
  - task: lint_markdown
    status: passed
  - task: lint_package_json
    status: na
  - task: lint_repl_help
    status: passed
  - task: lint_javascript_src
    status: passed
  - task: lint_javascript_cli
    status: na
  - task: lint_javascript_examples
    status: na
  - task: lint_javascript_tests
    status: passed
  - task: lint_javascript_benchmarks
    status: na
  - task: lint_python
    status: na
  - task: lint_r
    status: na
  - task: lint_c_src
    status: na
  - task: lint_c_examples
    status: na
  - task: lint_c_benchmarks
    status: na
  - task: lint_c_tests_fixtures
    status: na
  - task: lint_shell
    status: na
  - task: lint_typescript_declarations
    status: passed
  - task: lint_typescript_tests
    status: na
  - task: lint_license_headers
    status: passed
---

Author: gururaj1512

lib/node_modules/@stdlib/stats/array/min-by/README.md

@@ -57,11 +57,11 @@ The function has the following parameters:
 -   **clbk**: callback function.
 -   **thisArg**: execution context (_optional_).
 
-The invoked callback is provided four arguments:
+The invoked callback is provided three arguments:
 
--   **value**: array element.
--   **aidx**: array index.
--   **array**: input array/collection.
+-   **value**: current array element.
+-   **index**: current array index.
+-   **array**: input array.
 
 To set the callback execution context, provide a `thisArg`.
 

lib/node_modules/@stdlib/stats/array/min-by/docs/repl.txt

@@ -6,8 +6,8 @@
 
     The callback function is provided three arguments:
 
-    - value: array element.
-    - aidx: array index.
+    - value: current array element.
+    - index: current array index.
     - array: the input array.
 
     The callback function should return a numeric value.

lib/node_modules/@stdlib/stats/array/min-by/docs/types/index.d.ts

@@ -32,44 +32,44 @@ type InputArray = NumericArray | Collection<number> | AccessorArrayLike<number>;
 *
 * @returns accessed value
 */
-type Nullary<U> = ( this: U ) => number | void;
+type Nullary<ThisArg> = ( this: ThisArg ) => number | void;
 
 /**
 * Returns an accessed value.
 *
-* @param value - array element
+* @param value - current array element
 * @returns accessed value
 */
-type Unary<T, U> = ( this: U, value: T ) => number | void;
+type Unary<T, ThisArg> = ( this: ThisArg, value: T ) => number | void;
 
 /**
 * Returns an accessed value.
 *
-* @param value - array element
-* @param aidx - array index
+* @param value - current array element
+* @param index - current array index
 * @returns accessed value
 */
-type Binary<T, U> = ( this: U, value: T, aidx: number ) => number | void;
+type Binary<T, ThisArg> = ( this: ThisArg, value: T, index: number ) => number | void;
 
 /**
 * Returns an accessed value.
 *
-* @param value - array element
-* @param aidx - array index
+* @param value - current array element
+* @param index - current array index
 * @param array - input array
 * @returns accessed value
 */
-type Ternary<T, U> = ( this: U, value: T, aidx: number, array: Collection<T> ) => number | void;
+type Ternary<T, U, ThisArg> = ( this: ThisArg, value: T, index: number, array: U ) => number | void;
 
 /**
 * Returns an accessed value.
 *
-* @param value - array element
-* @param aidx - array index
+* @param value - current array element
+* @param index - current array index
 * @param array - input array
 * @returns accessed value
 */
-type Callback<T, U> = Nullary<U> | Unary<T, U> | Binary<T, U> | Ternary<T, U>;
+type Callback<T, U, ThisArg> = Nullary<ThisArg> | Unary<T, ThisArg> | Binary<T, ThisArg> | Ternary<T, U, ThisArg>;
 
 /**
 * Computes the minimum value of an array via a callback function.
@@ -89,7 +89,7 @@ type Callback<T, U> = Nullary<U> | Unary<T, U> | Binary<T, U> | Ternary<T, U>;
 * var v = minBy( x, accessor );
 * // returns -10.0
 */
-declare function minBy<T = number, U = unknown>( x: InputArray, clbk: Callback<T, U>, thisArg?: ThisParameterType<Callback<T, U>> ): number;
+declare function minBy<T = number, U extends InputArray = InputArray, ThisArg = unknown>( x: U, clbk: Callback<T, U, ThisArg>, thisArg?: ThisParameterType<Callback<T, U, ThisArg>> ): number;
 
 
 // EXPORTS //

lib/node_modules/@stdlib/stats/array/min-by/lib/main.js

@@ -46,6 +46,7 @@ var GENERIC_DTYPE = 'generic';
 * @param {*} [thisArg] - execution context
 * @throws {TypeError} first argument must be an array-like object
 * @throws {TypeError} first argument must have a supported data type
+* @throws {TypeError} second argument must be a function
 * @returns {number} minimum value
 *
 * @example
@@ -68,7 +69,7 @@ function minBy( x, clbk, thisArg ) {
 		throw new TypeError( format( 'invalid argument. First argument must have one of the following data types: "%s". Data type: `%s`.', join( IDTYPES, '", "' ), dt ) );
 	}
 	if ( !isFunction( clbk ) ) {
-		throw new TypeError( format( 'invalid argument. Callback function must be a function. Value: `%s`.', clbk ) );
+		throw new TypeError( format( 'invalid argument. Second argument must be a function. Value: `%s`.', clbk ) );
 	}
 	return strided( x.length, x, 1, 0, wrapper );
 

lib/node_modules/@stdlib/stats/array/min-by/test/test.js

@@ -74,7 +74,7 @@ tape( 'the function throws an error if provided a first argument which is not an
 
 	function badValue( value ) {
 		return function badValue() {
-			minBy( value );
+			minBy( value, accessor );
 		};
 	}
 });
@@ -94,12 +94,12 @@ tape( 'the function throws an error if provided a first argument which has an un
 
 	function badValue( value ) {
 		return function badValue() {
-			minBy( value );
+			minBy( value, accessor );
 		};
 	}
 });
 
-tape( 'the function throws an error if provided a callback function argument which is not a function', function test( t ) {
+tape( 'the function throws an error if provided a second argument which is not a function', function test( t ) {
 	var values;
 	var i;
 	var x;
@@ -128,35 +128,6 @@ tape( 'the function throws an error if provided a callback function argument whi
 	}
 });
 
-tape( 'the function throws an error if provided a callback function argument which is not a function (options)', function test( t ) {
-	var values;
-	var i;
-	var x;
-
-	x = [ 1.0, -2.0, -4.0, 5.0, 0.0, 3.0 ];
-	values = [
-		'5',
-		5,
-		NaN,
-		null,
-		void 0,
-		true,
-		[],
-		{}
-	];
-
-	for ( i = 0; i < values.length; i++ ) {
-		t.throws( badValue( values[i] ), TypeError, 'throws a type error when provided '+values[i] );
-	}
-	t.end();
-
-	function badValue( value ) {
-		return function badValue() {
-			minBy( x, value, {} );
-		};
-	}
-});
-
 tape( 'the function calculates the minimum value of an array via a callback function', function test( t ) {
 	var x;
 	var v;
@@ -231,20 +202,79 @@ tape( 'the function calculates the minimum value of an array (array-like object)
 });
 
 tape( 'the function supports providing a callback execution context', function test( t ) {
+	var expected;
+	var indices;
+	var values;
+	var arrays;
 	var ctx;
 	var x;
 
 	x = [ 1.0, 2.0, 3.0, 4.0, 5.0 ];
 	ctx = {
 		'count': 0
 	};
+	indices = [];
+	values = [];
+	arrays = [];
 	minBy( x, accessor, ctx );
 
 	t.strictEqual( ctx.count, x.length, 'returns expected value' );
+
+	expected = [ 0, 1, 2, 3, 4 ];
+	t.deepEqual( indices, expected, 'returns expected value' );
+
+	expected = [ 1.0, 2.0, 3.0, 4.0, 5.0 ];
+	t.deepEqual( values, expected, 'returns expected value' );
+
+	expected = [ x, x, x, x, x ];
+	t.deepEqual( arrays, expected, 'returns expected value' );
+	t.end();
+
+	function accessor( v, idx, arr ) {
+		this.count += 1; // eslint-disable-line no-invalid-this
+		indices.push( idx );
+		values.push( v );
+		arrays.push( arr );
+		return v * 2.0;
+	}
+});
+
+tape( 'the function supports providing a callback execution context (accessors)', function test( t ) {
+	var expected;
+	var indices;
+	var values;
+	var arrays;
+	var ctx;
+	var ax;
+	var x;
+
+	x = [ 1.0, 2.0, 3.0, 4.0, 5.0 ];
+	ax = toAccessorArray( x );
+	ctx = {
+		'count': 0
+	};
+	indices = [];
+	values = [];
+	arrays = [];
+	minBy( ax, accessor, ctx );
+
+	t.strictEqual( ctx.count, x.length, 'returns expected value' );
+
+	expected = [ 0, 1, 2, 3, 4 ];
+	t.deepEqual( indices, expected, 'returns expected value' );
+
+	expected = [ 1.0, 2.0, 3.0, 4.0, 5.0 ];
+	t.deepEqual( values, expected, 'returns expected value' );
+
+	expected = [ ax, ax, ax, ax, ax ];
+	t.deepEqual( arrays, expected, 'returns expected value' );
 	t.end();
 
-	function accessor( v ) {
+	function accessor( v, idx, arr ) {
 		this.count += 1; // eslint-disable-line no-invalid-this
+		indices.push( idx );
+		values.push( v );
+		arrays.push( arr );
 		return v * 2.0;
 	}
 });
@@ -261,13 +291,13 @@ tape( 'if provided an empty array, the function returns `NaN` (accessors)', func
 	t.end();
 });
 
-tape( 'if provided an array containing a single element, the function returns the first element applying callback function', function test( t ) {
+tape( 'if provided an array containing a single element, the function returns the result of applying a provided callback function to that element', function test( t ) {
 	var v = minBy( [ 1.0 ], accessor );
 	t.strictEqual( v, 2.0, 'returns expected value' );
 	t.end();
 });
 
-tape( 'if provided an array containing a single element, the function returns the first element applying callback function (accessors)', function test( t ) {
+tape( 'if provided an array containing a single element, the function returns the result of applying a provided callback function to that element (accessors)', function test( t ) {
 	var v = minBy( toAccessorArray( [ 1.0 ] ), accessor );
 	t.strictEqual( v, 2.0, 'returns expected value' );
 	t.end();