diff --git a/lib/node_modules/@stdlib/stats/incr/nanmmae/README.md b/lib/node_modules/@stdlib/stats/incr/nanmmae/README.md
new file mode 100644
index 000000000000..b54fee912441
--- /dev/null
+++ b/lib/node_modules/@stdlib/stats/incr/nanmmae/README.md
@@ -0,0 +1,161 @@
+
+
+# incrnanmmae
+
+> Compute a moving [mean absolute error][mean-absolute-error] (MAE) incrementally, ignoring `NaN` values.
+
+
+
+For a window of size `W`, the [mean absolute error][mean-absolute-error] is defined as
+
+
+
+```math
+\mathop{\mathrm{MAE}} = \frac{1}{W} \sum_{i=0}^{W-1} |y_i - x_i|
+```
+
+
+
+
+
+
+
+
+
+
+
+## Usage
+
+```javascript
+var incrnanmmae = require( '@stdlib/stats/incr/nanmmae' );
+```
+
+#### incrnanmmae( window )
+
+Returns an accumulator function which incrementally computes a moving [mean absolute error][mean-absolute-error]. The `window` parameter defines the number of values over which to compute the moving [mean absolute error][mean-absolute-error], ignoring `NaN` values.
+
+```javascript
+var accumulator = incrnanmmae( 3 );
+```
+
+#### accumulator( \[x, y] )
+
+If provided input values `x` and `y`, the accumulator function returns an updated [mean absolute error][mean-absolute-error]. If not provided input values `x` and `y`, the accumulator function returns the current [mean absolute error][mean-absolute-error].
+
+```javascript
+var accumulator = incrnanmmae( 3 );
+
+var m = accumulator();
+// returns null
+
+// Fill the window...
+m = accumulator( 2.0, 3.0 ); // [(2.0,3.0)]
+// returns 1.0
+
+m = accumulator( NaN, 2.0 );
+// returns 1.0
+
+m = accumulator( -5.0, NaN );
+// returns 1.0
+
+m = accumulator( -1.0, 4.0 ); // [(2.0,3.0), (-1.0,4.0)]
+// returns 3.0
+
+m = accumulator( 3.0, 9.0 ); // [(2.0,3.0), (-1.0,4.0), (3.0,9.0)]
+// returns 4.0
+
+// Window begins sliding...
+m = accumulator( -7.0, 3.0 ); // [(-1.0,4.0), (3.0,9.0), (-7.0,3.0)]
+// returns 7.0
+
+m = accumulator( -5.0, -3.0 ); // [(3.0,9.0), (-7.0,3.0), (-5.0,-3.0)]
+// returns 6.0
+
+m = accumulator();
+// returns 6.0
+```
+
+
+
+
+
+
+
+## Notes
+
+- Input values are **not** type checked. If non-numeric inputs are possible, you are advised to type check and handle accordingly **before** passing the value to the accumulator function.
+- As `W` (x,y) pairs are needed to fill the window buffer, the first `W-1` returned values are calculated from smaller sample sizes. Until the window is full, each returned value is calculated from all provided values.
+- **Warning**: the [mean absolute error][mean-absolute-error] is scale-dependent and, thus, the measure should **not** be used to make comparisons between datasets having different scales.
+
+
+
+
+
+
+
+## Examples
+
+
+
+```javascript
+var uniform = require( '@stdlib/random/base/uniform' );
+var bernoulli = require( '@stdlib/random/base/bernoulli' );
+var incrnanmmae = require( '@stdlib/stats/incr/nanmmae' );
+
+// Initialize an accumulator:
+var accumulator = incrnanmmae( 5 );
+
+// For each simulated datum, update the moving mean absolute error...
+var v1;
+var v2;
+var i;
+for ( i = 0; i < 100; i++ ) {
+ v1 = ( bernoulli( 0.8 ) < 1 ) ? NaN : uniform( 0.0, 100.0 );
+ v2 = ( bernoulli( 0.8 ) < 1 ) ? NaN : uniform( 0.0, 100.0 );
+ accumulator( v1, v2 );
+}
+console.log( accumulator() );
+```
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+[mean-absolute-error]: https://en.wikipedia.org/wiki/Mean_absolute_error
+
+
+
+
diff --git a/lib/node_modules/@stdlib/stats/incr/nanmmae/benchmark/benchmark.js b/lib/node_modules/@stdlib/stats/incr/nanmmae/benchmark/benchmark.js
new file mode 100644
index 000000000000..a131e78dab5d
--- /dev/null
+++ b/lib/node_modules/@stdlib/stats/incr/nanmmae/benchmark/benchmark.js
@@ -0,0 +1,69 @@
+/**
+* @license Apache-2.0
+*
+* Copyright (c) 2025 The Stdlib Authors.
+*
+* Licensed under the Apache License, Version 2.0 (the "License");
+* you may not use this file except in compliance with the License.
+* You may obtain a copy of the License at
+*
+* http://www.apache.org/licenses/LICENSE-2.0
+*
+* Unless required by applicable law or agreed to in writing, software
+* distributed under the License is distributed on an "AS IS" BASIS,
+* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+* See the License for the specific language governing permissions and
+* limitations under the License.
+*/
+
+'use strict';
+
+// MODULES //
+
+var bench = require( '@stdlib/bench' );
+var randu = require( '@stdlib/random/base/randu' );
+var pkg = require( './../package.json' ).name;
+var incrnanmmae = require( './../lib' );
+
+
+// MAIN //
+
+bench( pkg, function benchmark( b ) {
+ var f;
+ var i;
+ b.tic();
+ for ( i = 0; i < b.iterations; i++ ) {
+ f = incrnanmmae( (i%5)+1 );
+ if ( typeof f !== 'function' ) {
+ b.fail( 'should return a function' );
+ }
+ }
+ b.toc();
+ if ( typeof f !== 'function' ) {
+ b.fail( 'should return a function' );
+ }
+ b.pass( 'benchmark finished' );
+ b.end();
+});
+
+bench( pkg+'::accumulator', function benchmark( b ) {
+ var acc;
+ var v;
+ var i;
+
+ acc = incrnanmmae( 5 );
+
+ b.tic();
+ for ( i = 0; i < b.iterations; i++ ) {
+ v = acc( randu()-0.5, randu()-0.5 );
+ if ( v !== v ) {
+ b.fail( 'should not return NaN' );
+ }
+ }
+ b.toc();
+ if ( v !== v ) {
+ b.fail( 'should not return NaN' );
+ }
+ b.pass( 'benchmark finished' );
+ b.end();
+});
diff --git a/lib/node_modules/@stdlib/stats/incr/nanmmae/docs/img/equation_mean_absolute_error.svg b/lib/node_modules/@stdlib/stats/incr/nanmmae/docs/img/equation_mean_absolute_error.svg
new file mode 100644
index 000000000000..48f2e2779e49
--- /dev/null
+++ b/lib/node_modules/@stdlib/stats/incr/nanmmae/docs/img/equation_mean_absolute_error.svg
@@ -0,0 +1,55 @@
+
\ No newline at end of file
diff --git a/lib/node_modules/@stdlib/stats/incr/nanmmae/docs/repl.txt b/lib/node_modules/@stdlib/stats/incr/nanmmae/docs/repl.txt
new file mode 100644
index 000000000000..c54e788361f9
--- /dev/null
+++ b/lib/node_modules/@stdlib/stats/incr/nanmmae/docs/repl.txt
@@ -0,0 +1,49 @@
+
+{{alias}}( W )
+ Returns an accumulator function which incrementally computes a moving
+ mean absolute error (MAE), ignoring `NaN` values.
+
+ The `W` parameter defines the number of values over which to compute the
+ moving mean absolute error.
+
+ If provided a value, the accumulator function returns an updated moving
+ mean absolute error. If not provided a value, the accumulator function
+ returns the current moving mean absolute error.
+
+ As `W` values are needed to fill the window buffer, the first `W-1` returned
+ values are calculated from smaller sample sizes. Until the window is full,
+ each returned value is calculated from all provided values.
+
+ Parameters
+ ----------
+ W: integer
+ Window size.
+
+ Returns
+ -------
+ acc: Function
+ Accumulator function.
+
+ Examples
+ --------
+ > var accumulator = {{alias}}( 3 );
+ > var m = accumulator()
+ null
+ > m = accumulator( 2.0, 3.0 )
+ 1.0
+ > m = accumulator( NaN, 2.0 )
+ 1.0
+ > m = accumulator( -5.0, NaN )
+ 1.0
+ > m = accumulator( -5.0, 2.0 )
+ 4.0
+ > m = accumulator( 3.0, 2.0 )
+ 3.0
+ > m = accumulator( 5.0, -2.0 )
+ 5.0
+ > m = accumulator()
+ 5.0
+
+ See Also
+ --------
+
diff --git a/lib/node_modules/@stdlib/stats/incr/nanmmae/docs/types/index.d.ts b/lib/node_modules/@stdlib/stats/incr/nanmmae/docs/types/index.d.ts
new file mode 100644
index 000000000000..9be00d4de14c
--- /dev/null
+++ b/lib/node_modules/@stdlib/stats/incr/nanmmae/docs/types/index.d.ts
@@ -0,0 +1,74 @@
+/*
+* @license Apache-2.0
+*
+* Copyright (c) 2025 The Stdlib Authors.
+*
+* Licensed under the Apache License, Version 2.0 (the "License");
+* you may not use this file except in compliance with the License.
+* You may obtain a copy of the License at
+*
+* http://www.apache.org/licenses/LICENSE-2.0
+*
+* Unless required by applicable law or agreed to in writing, software
+* distributed under the License is distributed on an "AS IS" BASIS,
+* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+* See the License for the specific language governing permissions and
+* limitations under the License.
+*/
+
+// TypeScript Version: 4.1
+
+/**
+* If provided input values, the accumulator function returns an updated mean absolute error. If not provided input values, the accumulator function returns the current mean absolute error.
+*
+* @param x - input value
+* @param y - input value
+* @returns mean absolute error or null
+*/
+type accumulator = ( x?: number, y?: number ) => number | null;
+
+/**
+* Returns an accumulator function which incrementally computes a moving mean absolute error, ignoring `NaN` values.
+*
+* ## Notes
+*
+* - The `W` parameter defines the number of values over which to compute the moving mean absolute error.
+* - As `W` values are needed to fill the window buffer, the first `W-1` returned values are calculated from smaller sample sizes. Until the window is full, each returned value is calculated from all provided values.
+*
+* @param W - window size
+* @throws must provide a positive integer
+* @returns accumulator function
+*
+* @example
+* var accumulator = incrnanmmae( 3 );
+*
+* var m = accumulator();
+* // returns null
+*
+* m = accumulator( 2.0, 3.0 );
+* // returns 1.0
+*
+* m = accumulator( NaN, 2.0 );
+* // returns 1.0
+*
+* m = accumulator( -5.0, NaN );
+* // returns 1.0
+*
+* m = accumulator( -5.0, 2.0 );
+* // returns 4.0
+*
+* m = accumulator( 3.0, 2.0 );
+* // returns 3.0
+*
+* m = accumulator( 5.0, -2.0 );
+* // returns 5.0
+*
+* m = accumulator();
+* // returns 5.0
+*/
+declare function incrnanmmae( W: number ): accumulator;
+
+
+// EXPORTS //
+
+export = incrnanmmae;
diff --git a/lib/node_modules/@stdlib/stats/incr/nanmmae/docs/types/test.ts b/lib/node_modules/@stdlib/stats/incr/nanmmae/docs/types/test.ts
new file mode 100644
index 000000000000..1b533f77df96
--- /dev/null
+++ b/lib/node_modules/@stdlib/stats/incr/nanmmae/docs/types/test.ts
@@ -0,0 +1,74 @@
+/*
+* @license Apache-2.0
+*
+* Copyright (c) 2025 The Stdlib Authors.
+*
+* Licensed under the Apache License, Version 2.0 (the "License");
+* you may not use this file except in compliance with the License.
+* You may obtain a copy of the License at
+*
+* http://www.apache.org/licenses/LICENSE-2.0
+*
+* Unless required by applicable law or agreed to in writing, software
+* distributed under the License is distributed on an "AS IS" BASIS,
+* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+* See the License for the specific language governing permissions and
+* limitations under the License.
+*/
+
+import incrnanmmae = require( './index' );
+
+
+// TESTS //
+
+// The function returns an accumulator function...
+{
+ incrnanmmae( 3 ); // $ExpectType accumulator
+}
+
+// The compiler throws an error if the function is provided an argument that is not a number...
+{
+ incrnanmmae( '5' ); // $ExpectError
+ incrnanmmae( true ); // $ExpectError
+ incrnanmmae( false ); // $ExpectError
+ incrnanmmae( null ); // $ExpectError
+ incrnanmmae( undefined ); // $ExpectError
+ incrnanmmae( [] ); // $ExpectError
+ incrnanmmae( {} ); // $ExpectError
+ incrnanmmae( ( x: number ): number => x ); // $ExpectError
+}
+
+// The compiler throws an error if the function is provided an invalid number of arguments...
+{
+ incrnanmmae(); // $ExpectError
+ incrnanmmae( 2, 3 ); // $ExpectError
+}
+
+// The function returns an accumulator function which returns an accumulated result...
+{
+ const acc = incrnanmmae( 3 );
+
+ acc(); // $ExpectType number | null
+ acc( 3.14, 2.0 ); // $ExpectType number | null
+}
+
+// The compiler throws an error if the returned accumulator function is provided invalid arguments...
+{
+ const acc = incrnanmmae( 3 );
+
+ acc( '5', 2.0 ); // $ExpectError
+ acc( true, 2.0 ); // $ExpectError
+ acc( false, 2.0 ); // $ExpectError
+ acc( null, 2.0 ); // $ExpectError
+ acc( [], 2.0 ); // $ExpectError
+ acc( {}, 2.0 ); // $ExpectError
+ acc( ( x: number ): number => x, 2.0 ); // $ExpectError
+
+ acc( 3.14, '5' ); // $ExpectError
+ acc( 3.14, true ); // $ExpectError
+ acc( 3.14, false ); // $ExpectError
+ acc( 3.14, null ); // $ExpectError
+ acc( 3.14, [] ); // $ExpectError
+ acc( 3.14, {} ); // $ExpectError
+ acc( 3.14, ( x: number ): number => x ); // $ExpectError
+}
diff --git a/lib/node_modules/@stdlib/stats/incr/nanmmae/examples/index.js b/lib/node_modules/@stdlib/stats/incr/nanmmae/examples/index.js
new file mode 100644
index 000000000000..c66e4c7aa5dd
--- /dev/null
+++ b/lib/node_modules/@stdlib/stats/incr/nanmmae/examples/index.js
@@ -0,0 +1,41 @@
+/**
+* @license Apache-2.0
+*
+* Copyright (c) 2025 The Stdlib Authors.
+*
+* Licensed under the Apache License, Version 2.0 (the "License");
+* you may not use this file except in compliance with the License.
+* You may obtain a copy of the License at
+*
+* http://www.apache.org/licenses/LICENSE-2.0
+*
+* Unless required by applicable law or agreed to in writing, software
+* distributed under the License is distributed on an "AS IS" BASIS,
+* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+* See the License for the specific language governing permissions and
+* limitations under the License.
+*/
+
+'use strict';
+
+// MODULES //
+
+var uniform = require( '@stdlib/random/base/uniform' );
+var bernoulli = require( '@stdlib/random/base/bernoulli' );
+var incrnanmmae = require( './../lib' );
+
+// Initialize an accumulator:
+var accumulator = incrnanmmae( 5 );
+
+// For each simulated datum, update the moving mean absolute error...
+console.log( '\nValue\tValue\tMean\n' );
+var err;
+var v1;
+var v2;
+var i;
+for ( i = 0; i < 100; i++ ) {
+ v1 = ( bernoulli( 0.8 ) < 1 ) ? NaN : uniform( 0.0, 100.0 );
+ v2 = ( bernoulli( 0.8 ) < 1 ) ? NaN : uniform( 0.0, 100.0 );
+ err = accumulator( v1, v2 );
+ console.log( '%d\t%d\t%d', v1.toFixed( 3 ), v2.toFixed( 3 ), ( err === null ) ? NaN : err.toFixed( 3 ) );
+}
diff --git a/lib/node_modules/@stdlib/stats/incr/nanmmae/lib/index.js b/lib/node_modules/@stdlib/stats/incr/nanmmae/lib/index.js
new file mode 100644
index 000000000000..94b8561f7ebf
--- /dev/null
+++ b/lib/node_modules/@stdlib/stats/incr/nanmmae/lib/index.js
@@ -0,0 +1,63 @@
+/**
+* @license Apache-2.0
+*
+* Copyright (c) 2025 The Stdlib Authors.
+*
+* Licensed under the Apache License, Version 2.0 (the "License");
+* you may not use this file except in compliance with the License.
+* You may obtain a copy of the License at
+*
+* http://www.apache.org/licenses/LICENSE-2.0
+*
+* Unless required by applicable law or agreed to in writing, software
+* distributed under the License is distributed on an "AS IS" BASIS,
+* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+* See the License for the specific language governing permissions and
+* limitations under the License.
+*/
+
+'use strict';
+
+/**
+* Compute a moving mean absolute error incrementally, ignoring `NaN` values.
+*
+* @module @stdlib/stats/incr/nanmmae
+*
+* @example
+* var incrnanmmae = require( '@stdlib/stats/incr/nanmmae' );
+*
+* var accumulator = incrnanmmae( 3 );
+*
+* var m = accumulator();
+* // returns null
+*
+* m = accumulator( 2.0, 3.0 );
+* // returns 1.0
+*
+* m = accumulator( NaN, 2.0 );
+* // returns 1.0
+*
+* m = accumulator( -5.0, NaN );
+* // returns 1.0
+*
+* m = accumulator( -5.0, 2.0 );
+* // returns 4.0
+*
+* m = accumulator( 3.0, 2.0 );
+* // returns 3.0
+*
+* m = accumulator( 5.0, -2.0 );
+* // returns 5.0
+*
+* m = accumulator();
+* // returns 5.0
+*/
+
+// MODULES //
+
+var main = require( './main.js' );
+
+
+// EXPORTS //
+
+module.exports = main;
diff --git a/lib/node_modules/@stdlib/stats/incr/nanmmae/lib/main.js b/lib/node_modules/@stdlib/stats/incr/nanmmae/lib/main.js
new file mode 100644
index 000000000000..560e4a6da4ac
--- /dev/null
+++ b/lib/node_modules/@stdlib/stats/incr/nanmmae/lib/main.js
@@ -0,0 +1,83 @@
+/**
+* @license Apache-2.0
+*
+* Copyright (c) 2025 The Stdlib Authors.
+*
+* Licensed under the Apache License, Version 2.0 (the "License");
+* you may not use this file except in compliance with the License.
+* You may obtain a copy of the License at
+*
+* http://www.apache.org/licenses/LICENSE-2.0
+*
+* Unless required by applicable law or agreed to in writing, software
+* distributed under the License is distributed on an "AS IS" BASIS,
+* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+* See the License for the specific language governing permissions and
+* limitations under the License.
+*/
+
+'use strict';
+
+// MODULES //
+
+var isnan = require( '@stdlib/math/base/assert/is-nan' );
+var incrmmae = require( '@stdlib/stats/incr/mmae' );
+
+/**
+* Returns an accumulator function which incrementally computes a moving mean absolute error, ignoring `NaN` values.
+*
+* @param {PositiveInteger} W - window size
+* @throws {TypeError} must provide a positive integer
+* @returns {Function} accumulator function
+*
+* @example
+* var accumulator = incrnanmmae( 3 );
+*
+* var m = accumulator();
+* // returns null
+*
+* m = accumulator( 2.0, 3.0 );
+* // returns 1.0
+*
+* m = accumulator( NaN, 2.0 );
+* // returns 1.0
+*
+* m = accumulator( -5.0, NaN );
+* // returns 1.0
+*
+* m = accumulator( -5.0, 2.0 );
+* // returns 4.0
+*
+* m = accumulator( 3.0, 2.0 );
+* // returns 3.0
+*
+* m = accumulator( 5.0, -2.0 );
+* // returns 5.0
+*
+* m = accumulator();
+* // returns 5.0
+*/
+function incrnanmmae( W ) {
+ var mmae = incrmmae( W );
+ return accumulator;
+
+ /**
+ * If provided input values, the accumulator function returns an updated mean absolute error. If not provided input values, the accumulator function returns the current mean absolute error.
+ *
+ * @private
+ * @param {number} [x] - input value
+ * @param {number} [y] - input value
+ * @returns {(number|null)} mean absolute error or null
+ */
+ function accumulator( x, y ) {
+ if ( arguments.length === 0 || isnan( x ) || isnan( y ) ) {
+ return mmae();
+ }
+ return mmae( x, y );
+ }
+}
+
+
+// EXPORTS //
+
+module.exports = incrnanmmae;
diff --git a/lib/node_modules/@stdlib/stats/incr/nanmmae/package.json b/lib/node_modules/@stdlib/stats/incr/nanmmae/package.json
new file mode 100644
index 000000000000..45ba9dc58afd
--- /dev/null
+++ b/lib/node_modules/@stdlib/stats/incr/nanmmae/package.json
@@ -0,0 +1,83 @@
+{
+ "name": "@stdlib/stats/incr/nanmmae",
+ "version": "0.0.0",
+ "description": "Compute a moving mean absolute error (MAE) incrementally, ignoring `NaN` values.",
+ "license": "Apache-2.0",
+ "author": {
+ "name": "The Stdlib Authors",
+ "url": "https://github.com/stdlib-js/stdlib/graphs/contributors"
+ },
+ "contributors": [
+ {
+ "name": "The Stdlib Authors",
+ "url": "https://github.com/stdlib-js/stdlib/graphs/contributors"
+ }
+ ],
+ "main": "./lib",
+ "directories": {
+ "benchmark": "./benchmark",
+ "doc": "./docs",
+ "example": "./examples",
+ "lib": "./lib",
+ "test": "./test"
+ },
+ "types": "./docs/types",
+ "scripts": {},
+ "homepage": "https://github.com/stdlib-js/stdlib",
+ "repository": {
+ "type": "git",
+ "url": "git://github.com/stdlib-js/stdlib.git"
+ },
+ "bugs": {
+ "url": "https://github.com/stdlib-js/stdlib/issues"
+ },
+ "dependencies": {},
+ "devDependencies": {},
+ "engines": {
+ "node": ">=0.10.0",
+ "npm": ">2.7.0"
+ },
+ "os": [
+ "aix",
+ "darwin",
+ "freebsd",
+ "linux",
+ "macos",
+ "openbsd",
+ "sunos",
+ "win32",
+ "windows"
+ ],
+ "keywords": [
+ "stdlib",
+ "stdmath",
+ "statistics",
+ "stats",
+ "mathematics",
+ "math",
+ "average",
+ "avg",
+ "mean",
+ "error",
+ "err",
+ "absolute",
+ "mae",
+ "incremental",
+ "accumulator",
+ "moving mean",
+ "moving average",
+ "sliding window",
+ "sliding",
+ "window",
+ "moving",
+ "time series",
+ "timeseries",
+ "forecasting",
+ "forecast",
+ "manhattan",
+ "cityblock",
+ "city-block",
+ "distance",
+ "dist"
+ ]
+}
diff --git a/lib/node_modules/@stdlib/stats/incr/nanmmae/test/test.js b/lib/node_modules/@stdlib/stats/incr/nanmmae/test/test.js
new file mode 100644
index 000000000000..7b34fb6e7cef
--- /dev/null
+++ b/lib/node_modules/@stdlib/stats/incr/nanmmae/test/test.js
@@ -0,0 +1,224 @@
+/**
+* @license Apache-2.0
+*
+* Copyright (c) 2025 The Stdlib Authors.
+*
+* Licensed under the Apache License, Version 2.0 (the "License");
+* you may not use this file except in compliance with the License.
+* You may obtain a copy of the License at
+*
+* http://www.apache.org/licenses/LICENSE-2.0
+*
+* Unless required by applicable law or agreed to in writing, software
+* distributed under the License is distributed on an "AS IS" BASIS,
+* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+* See the License for the specific language governing permissions and
+* limitations under the License.
+*/
+
+'use strict';
+
+// MODULES //
+
+var tape = require( 'tape' );
+var isnan = require( '@stdlib/math/base/assert/is-nan' );
+var incrnanmmae = require( './../lib' );
+
+
+// TESTS //
+
+tape( 'main export is a function', function test( t ) {
+ t.ok( true, __filename );
+ t.strictEqual( typeof incrnanmmae, 'function', 'main export is a function' );
+ t.end();
+});
+
+tape( 'the function throws an error if not provided a positive integer', function test( t ) {
+ var values;
+ var i;
+
+ values = [
+ '5',
+ -5.0,
+ 0.0,
+ 3.14,
+ true,
+ null,
+ void 0,
+ NaN,
+ [],
+ {},
+ function noop() {}
+ ];
+
+ for ( i = 0; i < values.length; i++ ) {
+ t.throws( badValue( values[i] ), TypeError, 'throws an error when provided '+values[i] );
+ }
+ t.end();
+
+ function badValue( value ) {
+ return function badValue() {
+ incrnanmmae( value );
+ };
+ }
+});
+
+tape( 'the function returns an accumulator function', function test( t ) {
+ t.equal( typeof incrnanmmae( 3 ), 'function', 'returns expected value' );
+ t.end();
+});
+
+tape( 'the accumulator function computes a moving mean absolute error incrementally', function test( t ) {
+ var expected;
+ var actual;
+ var data;
+ var acc;
+ var N;
+ var i;
+
+ data = [
+ [ 2.0, 3.0 ],
+ [ 3.0, -1.0 ],
+ [ 2.0, 5.0 ],
+ [ 4.0, -4.0 ],
+ [ 3.0, 0.0 ],
+ [ -4.0, 5.0 ]
+ ];
+ N = data.length;
+
+ acc = incrnanmmae( 3 );
+
+ actual = [];
+ for ( i = 0; i < N; i++ ) {
+ actual.push( acc( data[i][0], data[i][1] ) );
+ }
+ expected = [ 1.0, 2.5, 8.0/3.0, 5.0, 14.0/3.0, 20.0/3.0 ];
+
+ t.deepEqual( actual, expected, 'returns expected values' );
+ t.end();
+});
+
+tape( 'if not provided an input value, the accumulator function returns the current mean absolute error', function test( t ) {
+ var data;
+ var acc;
+ var i;
+
+ data = [
+ [ 2.0, 3.0 ],
+ [ 3.0, -5.0 ],
+ [ 1.0, 10.0 ]
+ ];
+ acc = incrnanmmae( 2 );
+ for ( i = 0; i < data.length; i++ ) {
+ acc( data[i][0], data[i][1] );
+ }
+ t.equal( acc(), 8.5, 'returns expected value' );
+ t.end();
+});
+
+tape( 'if data has yet to be provided, the accumulator function returns `null`', function test( t ) {
+ var acc = incrnanmmae( 3 );
+ t.equal( acc(), null, 'returns null' );
+ t.end();
+});
+
+tape( 'ignores `NaN` values and correctly computes moving mean absolute error', function test( t ) {
+ var expected;
+ var data;
+ var acc;
+ var v;
+ var i;
+
+ expected = [
+ null,
+ 2.14,
+ 2.14,
+ 2.14,
+ 2.14,
+ 2.14,
+ 2.14,
+ 2.14,
+ 2.14,
+ 2.14,
+ 2.14,
+ 2.14,
+ 2.14,
+ 2.14,
+ 2.14,
+ 2.14,
+ 2.14,
+ 2.14,
+ 2.14
+ ];
+
+ data = [
+ [ NaN, 1.0 ],
+ [ 3.14, 1.0 ],
+ [ 3.14, 1.0 ],
+ [ NaN, 1.0 ],
+ [ 3.14, 1.0 ],
+ [ 3.14, 1.0 ],
+ [ 3.14, 1.0 ],
+ [ NaN, 1.0 ],
+ [ 3.14, 1.0 ],
+ [ 3.14, 1.0 ],
+ [ 3.14, 1.0 ],
+ [ NaN, 1.0 ],
+ [ 3.14, 1.0 ],
+ [ 3.14, 1.0 ],
+ [ NaN, 1.0 ],
+ [ NaN, 1.0 ],
+ [ NaN, 1.0 ],
+ [ NaN, 1.0 ],
+ [ 3.14, 1.0 ]
+ ];
+
+ acc = incrnanmmae( 3 );
+
+ for ( i = 0; i < data.length; i++ ) {
+ v = acc( data[i][0], data[i][1] );
+ if ( isnan( expected[ i ] ) ) {
+ t.equal( isnan( v ), true, 'returns expected value for window '+i );
+ t.equal( isnan( acc() ), true, 'returns expected value for window '+i );
+ } else {
+ t.equal( v, expected[ i ], 'returns expected value for window '+i );
+ t.equal( acc(), expected[ i ], 'returns expected value for window '+i );
+ }
+ }
+
+ data = [
+ [ 1.0, NaN ],
+ [ 1.0, 3.14 ],
+ [ 1.0, 3.14 ],
+ [ 1.0, NaN ],
+ [ 1.0, 3.14 ],
+ [ 1.0, 3.14 ],
+ [ 1.0, 3.14 ],
+ [ 1.0, NaN ],
+ [ 1.0, 3.14 ],
+ [ 1.0, 3.14 ],
+ [ 1.0, 3.14 ],
+ [ 1.0, NaN ],
+ [ 1.0, 3.14 ],
+ [ 1.0, 3.14 ],
+ [ 1.0, NaN ],
+ [ 1.0, NaN ],
+ [ 1.0, NaN ],
+ [ 1.0, NaN ],
+ [ 1.0, 3.14 ]
+ ];
+
+ acc = incrnanmmae( 3 );
+
+ for ( i = 0; i < data.length; i++ ) {
+ v = acc( data[i][0], data[i][1] );
+ if ( isnan( expected[ i ] ) ) {
+ t.equal( isnan( v ), true, 'returns expected value for window '+i );
+ t.equal( isnan( acc() ), true, 'returns expected value for window '+i );
+ } else {
+ t.equal( v, expected[ i ], 'returns expected value for window '+i );
+ t.equal( acc(), expected[ i ], 'returns expected value for window '+i );
+ }
+ }
+ t.end();
+});