[javascript] Objects.keys(array), Object.getOwnPropertyNames(array), Object.entries(array)

* get an array of its keys

var lunch = {
    sandwich: 'turkey',
    chips: 'cape cod',
    drink: 'soda'
};

var keys = Object.keys(lunch);

returns enumerable properties

 

- var props = Object.getOwnPropertyNames(lunch)

returns both enumerable and non-enumerable properties

// returns an empty array:
Object.keys(Function.prototype);

// returns ["length", "name", "arguments", "caller", "constructor", "apply", "bind", "call", "toString"]
Object.getOwnPropertyNames(Function.prototype);

 

cf) Array.forEach(), Array.map() 

keys.forEach(function(key){console.log(key)});

 

* get an array of entries

var lunch = {
	sandwich: 'turkey',
	chips: 'cape cod',
	drink: 'soda'
};

// returns [['sandwich', 'turkey'], ['chips', 'cape code'], ['drink', 'soda']]
var entries = Object.entries(lunch);

 

* create an array from an object

var keys = ;
var entries = ;

for (var key in lunch) {
	if (lunch.hasOwnProperty(key)) {

		// Create an array of keys
		keys.push(key);

		// Create an array of entries
		entries.push([key, lunch[key]]);

	}
}

source :  [Go Make Things] Converting an object into an array with vanilla JS