@stdlib/utils-none-in-by NPM

noneInBy

Test whether every property of an object fails a test implemented by a predicate function.

Installation

npm install @stdlib/utils-none-in-by

Usage

var noneInBy = require( '@stdlib/utils-none-in-by' );

noneInBy( object, predicate[, thisArg ] )

Tests whether every property of an object fails a test implemented by a predicate function.

function isUnderage( age ) {
    return ( age < 18 );
}

var obj = {
    'a': 28,
    'b': 22,
    'c': 25
};

var bool = noneInBy( obj, isUnderage );
// returns true

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

function isUnderage( age ) {
    return ( age < 18 );
}

var obj = {
    'a': 12,
    'b': 22,
    'c': 25
};

var bool = noneInBy( obj, isUnderage );
// returns false

The invoked function is provided three agruments:

value: property value
key: property key
object: input object

To set the function execution context, provide a thisArg.

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

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

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

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

var mean = context.sum / context.count;
// returns 2.5

Notes

If the 1st argument is not an object or the second argument is not a fuction , the function throws a Type Error.

If provided an empty object, the function returns true.

function truthy() {
    return true;
}
var bool = noneInBy( {}, truthy );
// returns true

The function does not skip undefined elements.

function log( value, index ) {
    console.log( '%s: %s', index, value );
    return false;
}

var obj = {
    'a': 1,
    'b': NaN,
    'c': NaN,
    'd': 4
};

var bool = noneInBy( arr, log );
/* =>
    0: 1
    1: undefined
    2: undefined
    3: 4
*/

Examples

var noneInBy = require( '@stdlib/utils-none-in-by' );

function isUnderage( age ) {
    return age < 18;
}

var obj = {
    'a': 26,
    'b': 20,
    'c': 25
};

var bool = noneInBy( obj, isUnderage );
// returns true

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.