javascript在数组中查找具有特定属性的对象

Question

I need to make an extension to existing code, can't change it. There's this array:

var availableTags = [
        { label: "Yoga classes", category: "EDUCATIONAL" },
        { label: "Cooking classes", category: "EDUCATIONAL" },
        { label: "Cheese tastings", category: "EDUCATIONAL" },
        { label: "Maker Workshops", category: "PRACTICAL" },
        { label: "Seminars", category: "PRACTICAL" },
        //many more of these
];

Now I need to check if a text entered in an input box is included in one of the labels, eg if the user enters "Yoga classes" => OK, if "Yoga" => NOK, "sdsdf" => NOK, etc.

What is the best way to do this? I am not sure I can use Array.indexOf as I am not sure how to pass the Object to the function, I would try looping through the array (around 40 entries) and compare each object.

Answer 1

You need to loop over every item in availableTags and check whether that item's label is equal to some input. Try something like this:

var input = "Yoga classes";
var found = false;
for (var i = 0, j = availableTags.length; i < j; i++) {
    var cur = availableTags[i];
    if (cur.label === input) {
        found = true;
        break;
    }
}
console.log(found);

DEMO: http://jsfiddle.net/k4cp4/4/

Where this can easily be put into a function, like:

var checkMatch = (function () {
    var availableTags = [
        { label: "Yoga classes", category: "EDUCATIONAL" },
        { label: "Cooking classes", category: "EDUCATIONAL" },
        { label: "Cheese tastings", category: "EDUCATIONAL" },
        { label: "Maker Workshops", category: "PRACTICAL" },
        { label: "Seminars", category: "PRACTICAL" }
    ];

    return function (input) {
        var found = false;
        for (var i = 0, j = availableTags.length; i < j; i++) {
            var cur = availableTags[i];
            if (cur.label === input) {
                found = true;
                break;
            }
        }
        return found;
    };
})();

DEMO: http://jsfiddle.net/k4cp4/5/

This checks for an exact match. So if you want a case insensitive match, you can use:

if (cur.label.toLowerCase() === input.toLowerCase()) {

DEMO: http://jsfiddle.net/k4cp4/6/

If you want to see if any of the label s contain the input, you can use indexOf like:

if (cur.label.indexOf(input) > -1) {

DEMO: http://jsfiddle.net/k4cp4/7/

Answer 2

You can use Array.some method:

Tests whether some element in the array passes the test implemented by the provided function.

Then your code would look something like:

var isFound = availableTags.some(function(el) {
    return el.label === 'Yoga classes';
});

Note: some method needs to be shimmed.

Answer 3

var check = function(item) {    
    for(at in availableTags) {
       if(item == availableTags[at].label) {
          return true;
       }
    }
    return false;
}


console.log(check("Yoga classes"));