I have an array of event objects called events. Each event has markets, an array containing market objects. Inside here there is another array called outes, containing oute objects.

In this question, I asked for a [Underscore.js] way to find all of the events which have markets which have outes which have a property named test. The answer was:

// filter where condition is true
_.filter(events, function(evt) {

    // return true where condition is true for any market
    return _.any(evt.markets, function(mkt) {

        // return true where any oute has a "test" property defined
        return _.any(mkt.outes, function(outc) {
            return outc.test !== "undefined" && outc.test !== "bar";
        });
    });
});

This works great, but I'm wondering how I would alter it if I wanted to filter the outes for each market, so that market.outes only stored outes that were equal to bar. Currently, this is just giving me markets which have outes which have some set test properties. I want to strip out the ones that do not.

I have an array of event objects called events. Each event has markets, an array containing market objects. Inside here there is another array called outes, containing oute objects.

In this question, I asked for a [Underscore.js] way to find all of the events which have markets which have outes which have a property named test. The answer was:

// filter where condition is true
_.filter(events, function(evt) {

    // return true where condition is true for any market
    return _.any(evt.markets, function(mkt) {

        // return true where any oute has a "test" property defined
        return _.any(mkt.outes, function(outc) {
            return outc.test !== "undefined" && outc.test !== "bar";
        });
    });
});

This works great, but I'm wondering how I would alter it if I wanted to filter the outes for each market, so that market.outes only stored outes that were equal to bar. Currently, this is just giving me markets which have outes which have some set test properties. I want to strip out the ones that do not.

• javascript
• underscore.js

• Does it really work great? Your innermost .any() callback references "oute" but the parameter is "outc" ... – Pointy Commented May 30, 2012 at 20:55
• Also, that aside, it seems like you just need to flip from .any() to .all() with an opposite condition. In other words, go from "any that are ..." to "all that are not ..." – Pointy Commented May 30, 2012 at 20:55
• Can you provide an example? Not sure what you mean by 'opposite condition'. – user1082754 Commented May 30, 2012 at 20:57
• Do you want to remove them from the events / markets array(s) or do you want to create a new structure containing those outes? – Bergi Commented May 30, 2012 at 20:59
• Events should only contain markets that have outes with a test property. Outes should only contain outes that have a test property. I want to remove them from the outes array if it doesn't have a test property. – user1082754 Commented May 30, 2012 at 21:00

1 Answer 1

Make it a simple loop, using the splice method for the array removals:

var events = [{markets:[{outes:[{test:x},...]},...]},...];
for (var i=0; i<events.length; i++) {
    var mrks = events[i].markets;
    for (var j=0; j<mrks.length; j++) {
        var otcs = mrks[j].outes;
        for (var k=0; k<otcs.length; k++) {
            if (! ("test" in otcs[k]))
                 otcs.splice(k--, 1); // remove the oute from the array
        }
        if (otcs.length == 0)
            mrks.splice(j--, 1); // remove the market from the array
    }
    if (mrks.length == 0)
        events.splice(i--, 1); // remove the event from the array
}

This code will remove all outes that have no test property, all empty markets and all empty events from the events array.

An Underscore version might look like that:

events = _.filter(events, function(evt) {
    evt.markets = _.filter(evt.markets, function(mkt) {
        mkt.outes = _.filter(mkt.outes, function(otc) {
            return "test" in otc;
        });
        return mkt.outes.length > 0;
    });
    return evt.markets.length > 0;
});