refactor: update stats/incr/wmean to handle nonnegative weights

[anandkaranubc]

Resolves None

Description

What is the purpose of this pull request?

This pull request:

• Updates the implementation of stats/incr/wmean to correctly handle nonnegative weights (w_i >= 0) and ensures mu is updated only after encountering a non-zero weight.
• Adds corresponding test cases to validate the handling of zero weights.
• Updates existing test cases to correctly test the new outputs

Related Issues

Does this pull request have any related issues?

This pull request:

• resolves None

Questions

Any questions for reviewers of this pull request?

No.

Other

Any other information relevant to this pull request? This may include screenshots, references, and/or implementation notes.

• Now the implementation doesn't return NaN when weight is NaN or is not provided in the accumulator function. Instead it throws a TypeError.

Checklist

Please ensure the following tasks are completed before submitting this pull request.

• Read, understood, and followed the contributing guidelines.

---

@stdlib-js/reviewers

[kgryte]

Suggested change

	if (w === 0.0) {
	if ( w === 0.0 ) {

[kgryte]

Suggested change

	throw new TypeError( format( 'invalid argument. Must provide a nonnegative weight. Weight: `%s`.', w ) );
	throw new TypeError( format( 'invalid argument. Second argument must be a nonnegative number. Value: `%s`.', w ) );

[kgryte]

We prefer general error messages in order to minimize the total number of unique error messages in the code base. See error/tools/* for additional context.

[anandkaranubc]

Thanks Athan! It will help me in the further implementations.

Applied the suggestions!

[kgryte]

Suggested change

	* @throws {TypeError} must provide a nonnegative number as the weight
	* @throws {TypeError} second argument must be a nonnegative number

[kgryte]

Suggested change

	t.equal( acc( 2.0, 0.0 ), null, 'returns the previous accumulated mean' );
	t.equal( acc( 2.0, 2.0 ), 2.0, 'returns the current accumulated mean' );
	t.equal( acc( 5.0, 0.0 ), 2.0, 'returns the previous accumulated mean' );
	t.equal( acc( 2.0, 0.0 ), null, 'returns expected value' );
	t.equal( acc( 2.0, 2.0 ), 2.0, 'returns expected value' );
	t.equal( acc( 5.0, 0.0 ), 2.0, 'returns expected value' );

[kgryte]

Suggested change

	tape( 'the function throws an error if not provided a nonnegative number', function test( t ) {
	tape( 'the accumulator function throws an error if provided a second argument which is not a nonnegative number', function test( t ) {

[anandkaranubc]

/stdlib merge

[stdlib-bot]

Coverage Report

Package	Statements	Branches	Functions	Lines
stats/incr/wmean	$\color{green}189/189$ $\color{green}+100.00\%$	$\color{green}14/14$ $\color{green}+100.00\%$	$\color{green}2/2$ $\color{green}+100.00\%$	$\color{green}189/189$ $\color{green}+100.00\%$

The above coverage report was generated for the changes in this PR.

[kgryte]

/stdlib merge