npm install @stdlib/utils-async-some-by

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varsomeByAsync=require('@stdlib/utils-async-some-by');

Tests whether acollection contains at leastn elements which pass a test implemented by apredicate function.

functionpredicate(value,next){setTimeout(onTimeout,value);functiononTimeout(){console.log(value);/* =>            1000            2500            3000        */next(null,false);}}functiondone(error,bool){if(error){throwerror;}console.log(bool);// => false}vararr=[3000,2500,1000];someByAsync(arr,2,predicate,done);

The function immediately stops processingcollection elements and returnstrue for the test result upon receivingn truthy predicate result values.

functionpredicate(value,index,next){setTimeout(onTimeout,value);functiononTimeout(){if(index===1){returnnext(newError('beep'));}next(null,true);}}functiondone(error,bool){if(error){throwerror;}console.log(bool);// => true}vararr=[3000,2500,1000];someByAsync(arr,1,predicate,done);

The function accepts the followingoptions:

• limit: the maximum number of pending invocations at any one time. Default:infinity.
• series:boolean indicating whether to sequentially invoke thepredicate function for eachcollection element. Iftrue, the function setsoptions.limit=1. Default:false.
• thisArg: the execution context forpredicate.

By default, all elements are processed concurrently, which means that the function doesnot guarantee completion order. To process eachcollection element sequentially, set theseries option totrue.

functionpredicate(value,next){setTimeout(onTimeout,value);functiononTimeout(){console.log(value);/* =>            3000            2500            1000        */next(null,false);}}functiondone(error,bool){if(error){throwerror;}console.log(bool);// => false}vararr=[3000,2500,1000];varopts={'series':true};someByAsync(arr,2,opts,predicate,done);

To limit the maximum number of pending function invocations, set thelimit option.

functionpredicate(value,next){setTimeout(onTimeout,value);functiononTimeout(){console.log(value);/* =>            2500            3000            1000        */next(null,false);}}functiondone(error,bool){if(error){throwerror;}console.log(bool);// => false}vararr=[3000,2500,1000];varopts={'limit':2};someByAsync(arr,2,opts,predicate,done);

To set the execution context of thepredicate function, set thethisArg option.

functionpredicate(value,next){this.count+=1;setTimeout(onTimeout,value);functiononTimeout(){next(null,false);}}vararr=[3000,2500,1000];varcontext={'count':0};varopts={'thisArg':context};someByAsync(arr,2,opts,predicate,done);functiondone(error,bool){if(error){throwerror;}console.log(bool);// => falseconsole.log(context.count);// => 3}

When invoked, thepredicate function is provided a maximum of four arguments:

• value: collection value.
• index: collection index.
• collection: the inputcollection.
• next: a callback which should be called once thepredicate function has finished processing a collectionvalue.

The actual number of provided arguments depends on functionlength. If thepredicate function accepts two arguments, thepredicate function is providedvalue andnext. If thepredicate function accepts three arguments, thepredicate function is providedvalue,index, andnext. For every otherpredicate function signature, thepredicate function is provided all four arguments.

functionpredicate(value,i,collection,next){console.log('collection: %s. %d: %d',collection.join(','),i,value);/* =>        collection: 3000,2500,1000. 0: 3000        collection: 3000,2500,1000. 1: 2500        collection: 3000,2500,1000. 2: 1000    */setTimeout(onTimeout,value);functiononTimeout(){console.log(value);/* =>            1000            2500            3000        */next(null,false);}}functiondone(error,bool){if(error){throwerror;}console.log(bool);// => false}vararr=[3000,2500,1000];someByAsync(arr,2,predicate,done);

Returns afunction which invokes apredicate function once for each element in acollection.

functionpredicate(value,next){setTimeout(onTimeout,value);functiononTimeout(){console.log(value);next(null,false);}}functiondone(error,bool){if(error){throwerror;}console.log(bool);}varf=someByAsync.factory(predicate);vararr1=[3000,2500,1000];f(arr1,2,done);/* e.g., =>    1000    2500    3000    false*/vararr2=[300,250,100];f(arr2,2,done);/* e.g., =>    100    250    300    false*/

The function accepts the sameoptions assomeByAsync().

• Acollection may be either anArray,Typed Array, or an array-likeObject (excludingstrings andfunctions).
• If a provided function calls thenext callback with a truthyerror argument, the function suspends execution and immediately calls thedone callback for subsequenterror handling.
• The function doesnot support dynamiccollection resizing.
• The function doesnot skipundefined elements.
• If provided an emptycollection, the function calls thedone callback withfalse as the test result.
• NeithersomeByAsync nor the function returned by thefactory methodguarantee asynchronous execution. To guarantee asynchrony, wrap thedone callback in a function which either executes at the end of the current stack (e.g.,nextTick) or during a subsequent turn of the event loop (e.g.,setImmediate,setTimeout).

• @stdlib/utils-async/any-by:test whether at least one element in a collection passes a test implemented by a predicate function.
• @stdlib/utils-async/every-by:test whether all elements in a collection pass a test implemented by a predicate function.
• @stdlib/utils-async/for-each:invoke a function once for each element in a collection.
• @stdlib/utils-async/none-by:test whether all elements in a collection fail a test implemented by a predicate function.
• @stdlib/utils-some-by:test whether a collection contains at leastn elements which pass a test implemented by a predicate function.
• @stdlib/utils-async/some-by-right:test whether a collection contains at leastn elements which pass a test implemented by a predicate function, iterating from right to left.

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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