groupBy javascript

groupBy.js

function groupBy(jsonArray, fun) {
    return jsonArray.reduce(function(accumulator, object) {
        var value = fun(object);
        if (Array.isArray(accumulator[value])) {
            accumulator[value].push(object);
        } else {
            accumulator[value] = [object];
        }
        return accumulator;
    }, {});
}

TestCase("Group by", {
    "test group by": function () {
        assertEquals({3: ["foo", "bar", "baz"]}, groupBy(["foo", "bar", "baz"], function(string) { return string.length;}));

        assertEquals({"b": ["bar", "baz"], "f": ["foo"]}, groupBy(["foo", "bar", "baz"], function(string) { return string[0];}));
    }
});

jsTestDriver.conf

server: http://localhost:9876

load:
  - groupBy.js

lanceTest.sh

java -jar JsTestDriver-1.3.2.jar --port 9876 --tests all --config jsTestDriver.conf --browser  /usr/bin/firefox