iterConstant

Create an iterator which always returns the same value.

Usage

var iterConstant = require( '@stdlib/iter/constant' );

iterConstant( value[, options] )

Returns an iterator which always returns the same value.

var it = iterConstant( 3.14 );
// returns <Object>

var v = it.next().value;
// returns 3.14

v = it.next().value;
// returns 3.14

v = it.next().value;
// returns 3.14

// ...

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 a value property and a done property having a boolean 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 function supports the following options:

  • iter: number of iterations. Default: 1e308.

By default, the function returns an infinite iterator (i.e., an iterator which never ends). To limit the number of iterations, set the iter option.

var opts = {
    'iter': 2
};
var it = iterConstant( 3.14, opts );
// returns <Object>

var v = it.next().value;
// returns 3.14

v = it.next().value;
// returns 3.14

var bool = it.next().done;
// returns true

Notes

  • When provided an object reference, the returned iterator always returns the same reference.

    var arr = [ 1, 2, 3, 4 ];

var it = iterConstant( arr );
// returns <Object>

var v1 = it.next().value;
// returns [ 1, 2, 3, 4 ]

var bool = ( v1 === arr );
// returns true

var v2 = it.next().value;
// returns [ 1, 2, 3, 4 ]

bool = ( v2 === arr );
// returns true

// ...

    To avoid unwanted object mutation, copy a provided value before creating an iterator.

  • If an environment supports Symbol.iterator, the returned iterator is iterable.

Examples

var randu = require( '@stdlib/random/base/randu' );
var iterConstant = require( '@stdlib/iter/constant' );

// Create an iterator:
var opts = {
    'iter': 10
};
var it = iterConstant( randu(), opts );

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

See Also

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