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README.md

anyInBy

Test whether at least one property in an object passes a test implemented by a predicate function.

Usage

var anyInBy = require( '@stdlib/object/any-in-by' );

anyInBy( object, predicate[, thisArg ] )

Tests whether at least one property in an object passes a test implemented by a predicate function.

function isNegative( value ) {
    return ( value < 0 );
}

var obj = {
    'a': 1,
    'b': 2,
    'c': -1
};

var bool = anyInBy( obj, isNegative );
// returns true

If a predicate function returns a truthy value, the function immediately returns true.

function isPositive( value ) {
    if ( value < 0 ) {
        throw new Error( 'should never reach this line' );
    }
    return ( value > 0 );
}

var obj = {
    'a': 1,
    'b': -2,
    'c': 3
};

var bool = anyInBy( obj, isPositive );
// returns true

The invoked function is provided three arguments:

  • value: property value.
  • key: property key.
  • object: input object.

To set the function execution context, provide a thisArg.

function sum( value ) {
    this.sum += value;
    this.count += 1;
    return ( value < 0 );
}

var obj = {
    'a': 1,
    'b': 2,
    'c': 3,
    'd': -4
};

var context = {
    'sum': 0,
    'count': 0
};

var bool = anyInBy( obj, sum, context );
// returns true

var mean = context.sum / context.count;
// returns 0.5

Notes

  • The obj object may contain own properties as well as inherited properties from its prototype chain.

  • If provided an empty object, the function returns false.

    function alwaysTrue() {
    return true;
}
var bool = anyInBy( {}, alwaysTrue );
// returns false

Examples

var randu = require( '@stdlib/random/base/randu' );
var anyInBy = require( '@stdlib/object/any-in-by' );

function threshold( value ) {
    return ( value > 0.95 );
}

var bool;
var obj = {};
var i;

for ( i = 0; i < 100; i++ ) {
    obj[i] = randu();
}

bool = anyInBy( obj, threshold );
// returns <boolean>

See Also

  • @stdlib/utils/any-by: test whether at least one element in a collection passes a test implemented by a predicate function.
  • @stdlib/object/any-own-by: test whether whether any 'own' property of a provided object satisfies a predicate function.
  • @stdlib/object/every-in-by: test whether all properties (own and inherited) of an object pass a test implemented by a predicate function.
  • @stdlib/object/some-in-by: test whether an object contains at least n properties (own and inherited) which pass a test implemented by a predicate function.