iterFlow

Usage

var iterFlow = require( '@stdlib/iter/flow' );

iterFlow( methods )

Returns a fluent interface iterator constructor with a customized prototype based on provided methods.

var iterHead = require( '@stdlib/iter/head' );
var iterSome = require( '@stdlib/iter/some' );

// Create a mini-fluent interface having just the methods `head` and `some`:
var FluentIterator = iterFlow({
    'head': iterHead,
    'some': iterSome
});

The methods argument should be an object which maps constructor method names to iterator functions. Each iterator function should have the following function signature:

function iterFcn( iterator[, ...args] ) {...}

where

• iterator: an iterator
• ...args: additional iterator function arguments

When a fluent interface iterator method is invoked, the method invokes the corresponding iterator function with an iterator and provided method arguments.

If an iterator function returns an iterator, the corresponding fluent interface method returns a new fluent interface instance; otherwise, the corresponding fluent interface method returns the iterator function result.

FluentIterator( iterator )

Returns a new fluent interface iterator from a source iterator.

var array2iterator = require( '@stdlib/array/to-iterator' );
var iterHead = require( '@stdlib/iter/head' );
var iterSome = require( '@stdlib/iter/some' );

// Create a mini-fluent interface having just the methods `head` and `some`:
var FluentIterator = iterFlow({
    'head': iterHead,
    'some': iterSome
});

// Create a source iterator:
var src = array2iterator( [ 0, 0, 1, 1, 1, 0, 0, 1, 0, 1 ] );

// Convert the source iterator to a fluent interface iterator:
var it = new FluentIterator( src );

// Test if at least 3 of the first 5 iterated values are truthy:
var bool = it.head( 5 ).some( 3 );
// returns true

FluentIterator.prototype.next()

Returns an iterator protocol-compliant object containing the next iterated value (if one exists) assigned to a value property and a done property having a boolean value indicating whether the iterator is finished.

var array2iterator = require( '@stdlib/array/to-iterator' );
var iterHead = require( '@stdlib/iter/head' );
var iterSome = require( '@stdlib/iter/some' );

// Create a mini-fluent interface having just the methods `head` and `some`:
var FluentIterator = iterFlow({
    'head': iterHead,
    'some': iterSome
});

// Create a source iterator:
var src = array2iterator( [ 0, 0, 1, 1, 1, 0, 0, 1, 0, 1 ] );

// Create a fluent interface iterator:
var it1 = new FluentIterator( src );

// Invoke the `head` method to return an iterator limited to the first 5 source values:
var it2 = it1.head( 5 );

// Perform manual iteration...
var v;
while ( true ) {
    v = it2.next();
    if ( v.done ) {
        break;
    }
    console.log( v.value );
}

FluentIterator.prototype.return( [value] )

Closes a fluent interface iterator and returns a single (optional) argument in an iterator protocol-compliant object.

var array2iterator = require( '@stdlib/array/to-iterator' );
var iterHead = require( '@stdlib/iter/head' );
var iterSome = require( '@stdlib/iter/some' );

// Create a mini-fluent interface having just the methods `head` and `some`:
var FluentIterator = iterFlow({
    'head': iterHead,
    'some': iterSome
});

// Create a source iterator:
var src = array2iterator( [ 0, 0, 1, 1, 1, 0, 0, 1, 0, 1 ] );

// Create a fluent interface iterator:
var it1 = new FluentIterator( src );

// Invoke the `head` method to return an iterator limited to the first 5 source values:
var it2 = it1.head( 5 );

// Get the first value:
var v = it2.next().value;
// returns 0

// Get the second value:
v = it2.next().value;
// returns 0

// Get the third value:
v = it2.next().value;
// returns 1

// Close the iterator:
var bool = it2.return().done;
// returns true

// Attempt to get the fourth value:
v = it2.next().value;
// returns undefined