I want to return a filtered array containing only a specified value
var messages: [{
id: 1,
name: "John",
hashtag: ["#cool"]},
{id: 2,
name: "Bob",
hashtag: ["#cool", "#sweet"]},
{id: 3,
name: "Bob",
hashtag: ["#sweet"]} ];
// supposed to return the first two items in the array
var newArray = _.where(messages, {hashtag: "#cool"});
Here is a purely functional way you can do it with underscore, though, much prefer Ramda for this kind of thing:
var messages = [{
id: 1,
name: "John",
hashtag: ["#cool"]
},
{
id: 2,
name: "Bob",
hashtag: ["#cool", "#sweet"]
},
{
id: 3,
name: "Bob",
hashtag: ["#sweet"]
}
]
var newArray = _.filter(messages, _.compose(_.partial(_.contains, _, '#cool'), _.property('hashtag')))
console.log(newArray)<script src="https://cdnjs.cloudflare.com/ajax/libs/underscore.js/1.8.3/underscore-min.js"></script>you can good use Filter, but your object hast some syntax errors. the values must be in string. show this example:
var messages=[ {
id: 1,
name: "John",
hashtag: ["#cool"] },
{id: 2,
name: "Bob",
hashtag: ["#cool"," #sweet"] },
{id: 3,
name: "Bob",
hashtag: ["#sweet"]
}];
var newArray=messages.filter(function(task){ return task.hashtag.includes("#cool") });
console.log(newArray);You can't filter the array stored in "hashtag" using _.where (because it searches for a string in a key-value pair) but you can do it using _.filter
var filtered = _.filter( messages, function( message ){
return message['hashtag'].indexOf('#cool') !== -1;
} );
Little codepen to demonstrate it working: https://codepen.io/iwantwin/pen/oGWNzv
filterwith an explicit predicate function.wherewon't match a string against an array.messages.filter(m => m.hashtag.find(h => h === '#cool'))should be a plain and simple vanilla js function that is sufficient for your needs.