npm install @stdlib/iter-for-each

Alternatively,

• To load the package in a website via ascript tag without installation and bundlers, use theES Module available on theesm branch (seeREADME).
• If you are using Deno, visit thedeno branch (seeREADME for usage intructions).
• For use in Observable, or in browser/node environments, use theUniversal Module Definition (UMD) build available on theumd branch (seeREADME).

Thebranches.md file summarizes the available branches and displays a diagram illustrating their relationships.

To view installation and usage instructions specific to each branch build, be sure to explicitly navigate to the respective README files on each branch, as linked to above.

variterForEach=require('@stdlib/iter-for-each');

Returns an iterator which invokes afunction for each iterated valuebefore returning the iterated value.

vararray2iterator=require('@stdlib/array-to-iterator');functionassert(v){if(v!==v){thrownewError('should not be NaN');}}varit=iterForEach(array2iterator([1,2,3,4]),assert);// returns <Object>varr=it.next().value;// returns 1r=it.next().value;// returns 2r=it.next().value;// returns 3// ...

The returned iterator protocol-compliant object has the following properties:

• next: function which returns an iterator protocol-compliant object containing the next iterated value (if one exists) assigned to avalue property and adone property having aboolean value indicating whether the iterator is finished.
• return: function which closes an iterator and returns a single (optional) argument in an iterator protocol-compliant object.

The invoked function is provided two arguments:

• value: iterated value.
• index: iteration index (zero-based).

vararray2iterator=require('@stdlib/array-to-iterator');functionassert(v,i){if(i<0){thrownewError('unexpected Error');}}varit=iterForEach(array2iterator([1,2,3,4]),assert);// returns <Object>varr=it.next().value;// returns 1r=it.next().value;// returns 2r=it.next().value;// returns 3// ...

To set the execution context forfcn, provide athisArg.

vararray2iterator=require('@stdlib/array-to-iterator');functionassert(v){this.count+=1;if(v!==v){thrownewError('should not be NaN');}}varctx={'count':0};varit=iterForEach(array2iterator([1,2,3,4]),assert,ctx);// returns <Object>varr=it.next().value;// returns 1r=it.next().value;// returns 2r=it.next().value;// returns 3varcount=ctx.count;// returns 3

• If an environment supportsSymbol.iteratorand a provided iterator is iterable, the returned iterator is iterable.

• @stdlib/iter-map:create an iterator which invokes a function for each iterated value.

This package is part ofstdlib, a standard library for JavaScript and Node.js, with an emphasis on numerical and scientific computing. The library provides a collection of robust, high performance libraries for mathematics, statistics, streams, utilities, and more.

For more information on the project, filing bug reports and feature requests, and guidance on how to developstdlib, see the main projectrepository.

SeeLICENSE.

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