iterEveryBy

Test whether every iterated value passes a test implemented by a predicate function.

Installation

npm install @stdlib/iter-every-by

Usage

var iterEveryBy = require( '@stdlib/iter-every-by' );

iterEveryBy( iterator, predicate[, thisArg] )

Tests whether every iterated value passes a test implemented by a predicate function.

var array2iterator = require( '@stdlib/array-to-iterator' );

function predicate( v ) {
    return ( v > 0 );
}

var arr = array2iterator( [ 1, 1, 1, 1, 1 ] );

var bool = iterEveryBy( arr, predicate );
// returns true

If a provided iterator does not return any iterated values, the function returns true.

var array2iterator = require( '@stdlib/array-to-iterator' );

function predicate() {
    return true;
}

var bool = iterEveryBy( array2iterator( [] ), predicate );
// returns true

A predicate function is provided two arguments:

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

To set the execution context of the predicate function, provide a thisArg.

var array2iterator = require( '@stdlib/array-to-iterator' );

function predicate( v ) {
    this.count += 1;
    return ( v > 0 );
}

var arr = array2iterator( [ 1, 1, 0, 1, 1 ] );

var ctx = {
    'count': 0
};

var bool = iterEveryBy( arr, predicate, ctx );
// returns false

var n = ctx.count;
// returns 3

Notes

• The function immediately returns upon encountering a falsy return value.

Examples

var randu = require( '@stdlib/random-iter-randu' );
var iterEveryBy = require( '@stdlib/iter-every-by' );

function threshold( r ) {
    return ( r < 0.99 );
}

// Create an iterator which generates uniformly distributed pseudorandom numbers:
var opts = {
    'iter': 100
};
var riter = randu( opts );

// Determine if all values are below a threshold:
var bool = iterEveryBy( riter, threshold );
// returns <boolean>

console.log( bool );

See Also

• @stdlib/iter-any-by: test whether at least one iterated value passes a test implemented by a predicate function.
• @stdlib/iter-every: test whether all iterated values are truthy.
• @stdlib/iter-for-each: create an iterator which invokes a function for each iterated value before returning the iterated value.
• @stdlib/iter-none-by: test whether every iterated value fails a test implemented by a predicate function.
• @stdlib/iter-some-by: test whether at least n iterated values pass a test implemented by a predicate function.

Notice

This package is part of stdlib, 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 develop stdlib, see the main project repository.

Community

License

See LICENSE.

Copyright

Copyright © 2016-2024. The Stdlib Authors.