Full CSOM code used to demonstrate executing a search, and then combining result tables (i.e. for Office 365 and SharePoint hybrid deployments) into one resultset. See accompanying blog post for notes.

CSOMSearch_Full.js

var COB = COB || {};
COB.SharePoint = COB.SharePoint || {};
COB.SharePoint.HybridSearch = COB.SharePoint.HybridSearch || {};
COB.SharePoint.HybridSearch.Standard = COB.SharePoint.HybridSearch.Standard || {};
COB.SharePoint.HybridSearch.CustomInterleaving = COB.SharePoint.HybridSearch.CustomInterleaving || {};

var results;

COB.SharePoint.HybridSearch.GenericResult = (function (  ) {
    var __searchResult;

    __searchResult = function ( data ) {
        var self = this;
        self.Path = data.Path;
        self.Title = data.Title;
        self.Rank = data.Rank;
        self.LastModifiedTime = data.LastModifiedTime;
        self.Description = data.Description;
    };

    return {
        SearchResult: __searchResult
    };
}) ( );

COB.SharePoint.HybridSearch.Utility = {
    GetParameterByName: function (name) {
        name = name.replace(/[\[]/, "\\\[").replace(/[\]]/, "\\\]");
        var regex = new RegExp("[\\?&]" + name + "=([^&#]*)"),
        results = regex.exec(location.search);
        return results == null ? "" : decodeURIComponent(results[1].replace(/\+/g, " "));
    }
}

COB.SharePoint.HybridSearch.Standard = {
    someVar: '',

    Init: function() {
        $.getScript("/_layouts/15/SP.search.js",
            function () {
                COB.SharePoint.HybridSearch.Standard.RunSearch();
            });
    },

    RunSearch: function () {
       $('#CSOMSearchWP').text('');
        var clientContext = new SP.ClientContext(_spPageContextInfo.webAbsoluteUrl);
        var contextSite = clientContext.get_site();
        var keywordQuery = new Microsoft.SharePoint.Client.Search.Query.KeywordQuery(clientContext);
        var queryText = COB.SharePoint.HybridSearch.Utility.GetParameterByName('query');
        if (queryText == undefined) {
            queryText = 'sharepoint';
        }
        var enableInterleavingOverride = COB.SharePoint.HybridSearch.Utility.GetParameterByName('enableInterleaving');
        var enableInterleaving = (enableInterleavingOverride === 'true') ? true : false;

        $('#queryText').text(queryText);
        $('#interleaving').text(enableInterleaving);

        keywordQuery.set_queryText(queryText);
        // here's where we set the interleaving property..
        keywordQuery.set_enableInterleaving(enableInterleaving);
        
        var searchExecutor = new Microsoft.SharePoint.Client.Search.Query.SearchExecutor(clientContext);
        
        results = searchExecutor.executeQuery(keywordQuery);
        clientContext.executeQueryAsync(onSearchQuerySuccess, onSearchQueryError);
    }
}

COB.SharePoint.HybridSearch.CustomInterleaving = {
    Init: function () {
        $.getScript("/_layouts/15/SP.search.js",
            function () {
                COB.SharePoint.HybridSearch.CustomInterleaving.RunSearch();
            });
    },

    RunSearch: function () {
        $('#CSOMSearchWP_Interleaved').text('');
        var clientContext = new SP.ClientContext(_spPageContextInfo.webAbsoluteUrl);
        var contextSite = clientContext.get_site();
        var keywordQuery = new Microsoft.SharePoint.Client.Search.Query.KeywordQuery(clientContext);
        var queryText = COB.SharePoint.HybridSearch.Utility.GetParameterByName('query');
        if (queryText == undefined) {
            queryText = 'sharepoint';
        }
        var enableInterleavingOverride = COB.SharePoint.HybridSearch.Utility.GetParameterByName('enableInterleaving');
        var enableInterleaving = (enableInterleavingOverride === 'true') ? true : false;

        $('#queryText').text(queryText);
        $('#interleaving').text(enableInterleaving);

        keywordQuery.set_queryText(queryText);
        // here's where we set the interleaving property..
        keywordQuery.set_enableInterleaving(enableInterleaving);

        var searchExecutor = new Microsoft.SharePoint.Client.Search.Query.SearchExecutor(clientContext);

        results = searchExecutor.executeQuery(keywordQuery);
        clientContext.executeQueryAsync(onCustomInterleavedSearchQuerySuccess, onSearchQueryError);
    }
}

function renderResultTable(resultTable) {
    // since this code is used by two web parts, some presentation code here to decide what to do..  
    var selector;
    if ($('#CSOMSearchWP').is("DIV")) {
        selector = '#CSOMSearchWP';
    }
    if ($('#CSOMSearchWP_Interleaved').is("DIV")) {
        selector = '#CSOMSearchWP_Interleaved';
    }

    $(selector).append('<H1>Result table - ' + resultTable.TableType + '</H1>');

    $(selector).append('<table style=\'border-spacing: 3px; empty-cells: show; border: thin solid #C0C0C0\'>');
    $(selector).append('<tr style=\'background-color: #E4E4E4\' class=\'ms-webpart-titleText\'><td>Title</td><td>Url</td><td>Rank</td><td>Last modified</td><td>Description</td></tr>');

    $.each(resultTable.ResultRows, function () {
        $(selector).append('<tr>');
        $(selector).append('<td>' + this.Title + '</td>');
        $(selector).append('<td>' + this.Path + '</td>');
        $(selector).append('<td>' + this.Rank + '</td>');
        $(selector).append('<td>' + this.LastModifiedTime + '</td>');
        $(selector).append('<td>' + this.Description + '</td>');
        $(selector).append('</tr>');
    });
    $(selector).append('</table><br />');
}

function renderBestBetsResultTable(resultTable) {
    var selector;
    if ($('#CSOMSearchWP').is("DIV")) {
        selector = '#CSOMSearchWP';
    }
    if ($('#CSOMSearchWP_Interleaved').is("DIV")) {
        selector = '#CSOMSearchWP_Interleaved';
    }
    $(selector).append('<H1>Result table - ' + resultTable.TableType + '</H1>');

    $(selector).append('<table style=\'border-spacing: 3px; empty-cells: show; border: thin solid #C0C0C0\'>');
    $(selector).append('<tr style=\'background-color: #E4E4E4\' class=\'ms-webpart-titleText\'><td>Title</td><td>Url</td><td>Description</td></tr>');

    $.each(resultTable.ResultRows, function () {
        $(selector).append('<tr>');
        $(selector).append('<td>' + this.Title + '</td>');
        $(selector).append('<td>' + this.Url + '</td>');
        $(selector).append('<td>' + this.Description + '</td>');
        $(selector).append('</tr>');
    });
    $(selector).append('</table><br />');
}

function onSearchQuerySuccess() {
    $.each(results.m_value.ResultTables, function () {
        if (this.TableType === 'SpecialTermResults') {
            // show best bets if we have any..
            renderBestBetsResultTable(this)
        }
        else {
            renderResultTable(this);
        }
    });
}

function onCustomInterleavedSearchQuerySuccess() {
    var mergedResults = new Array();
    var fakeResultTable = {};

    $.each(results.m_value.ResultTables, function (index, resultTable) {
        if (resultTable.TableType === 'SpecialTermResults') {
            // show best bets if we have any..
            renderBestBetsResultTable(this)
        }
        else {
            console.log("Processing result table with " + resultTable.ResultRows.length + " rows");
            $.each(resultTable.ResultRows, function (index2, resultRow) {
                var item = new COB.SharePoint.HybridSearch.GenericResult.SearchResult(resultRow);
                // filtering on items which have a last modified time (for sorting by last modified)..
                if (item.LastModifiedTime != null) {
                    mergedResults.push(item);
                }
            });
        }
    });

    // now sort (using underscore.js)..
    // OPTION 1: enable this section to sort by rank (descending) [but remember, this is not valid across two SP instances, e.g. O365 and on-prem]..
    var sortedResults = _.sortBy(mergedResults, function (item) {
        // multiply Rank by -1 to get a DESC order sort..
        return (item.Rank * -1);
    });
    // OPTION 2: or enable this section to sort by last modified time..
    //var sortedResults = _.sortBy(mergedResults, function (item) {
    //    // multiply milliseconds by -1 to get a DESC order sort..
    //    return (item.LastModifiedTime != null) ? (item.LastModifiedTime.getTime() * -1): 0;
    //});
    // OPTION 3: enable this line to sort by rank (ascending) - mainly to demonstrate how to do this with underscore.js [but remember, this is not valid across two SP instances, e.g. O365 and on-prem]..
    //var sortedResults = _.sortBy(mergedResults, 'Rank');

    // now render sortedResults..
    fakeResultTable.ResultRows = sortedResults;
    fakeResultTable.TableType = 'merged with custom code';
    renderResultTable(fakeResultTable);
}

function onSearchQueryError() {
    if ($('#CSOMSearchWP').is("DIV")) {
        $('#CSOMSearchWP').text('Something went wrong executing the search :(');
    }

    if ($('#CSOMSearchWP_Interleaved').is("DIV")) {
        $('#CSOMSearchWP_Interleaved').text('Something went wrong executing the search :(');
    }
}

$(document).ready(function () {
    // since this JS file is added to multiple pages (would be changed for prod use!), just doing some hacky 
    // DOM detection here to work out which mode we're operating in..
    if ($('#CSOMSearchWP').is("DIV")) {
        SP.SOD.executeFunc('sp.js', 'SP.ClientContext', COB.SharePoint.HybridSearch.Standard.Init);
    }
    
    if ($('#CSOMSearchWP_Interleaved').is("DIV")) {
        SP.SOD.executeFunc('sp.js', 'SP.ClientContext', COB.SharePoint.HybridSearch.CustomInterleaving.Init);
    }
});