falcor-router/src/run/precedence/getExecutableMatches.js

A router DataSource constructor for falcor that allows you to model all your cloud data sources as a single JSON resource.

/* eslint-disable max-len */
var pathUtils = require('falcor-path-utils');
var collapse = pathUtils.collapse;
var stripPath = require('./../../operations/strip/stripPath');
var hasIntersection = require('./../../operations/matcher/intersection/hasIntersection');
/* eslint-enable max-len */

/**
 * takes in the set of ordered matches and pathSet that got those matches.
 * From there it will give back a list of matches to execute.
 */
module.exports = function getExecutableMatches(matches, pathSet) {
    var remainingPaths = pathSet;
    var matchAndPaths = [];
    var out = {
        matchAndPaths: matchAndPaths,
        unhandledPaths: false
    };
    for (var i = 0; i < matches.length && remainingPaths.length > 0; ++i) {
        var availablePaths = remainingPaths;
        var match = matches[i];

        remainingPaths = [];

        if (i > 0) {
            availablePaths = collapse(availablePaths);
        }

        // For every available path attempt to intersect.  If there
        // is an intersection then strip and replace.
        // any relative complements, add to remainingPaths
        for (var j = 0; j < availablePaths.length; ++j) {
            var path = availablePaths[j];
            if (hasIntersection(path, match.virtual)) {
                var stripResults = stripPath(path, match.virtual);
                matchAndPaths[matchAndPaths.length] = {
                    path: stripResults[0],
                    match: match
                };
                remainingPaths = remainingPaths.concat(stripResults[1]);
            } else if (i < matches.length - 1) {
                remainingPaths[remainingPaths.length] = path;
            }
        }
    }

    // Adds the remaining paths to the unhandled paths section.
    if (remainingPaths && remainingPaths.length) {
        out.unhandledPaths = remainingPaths;
    }

    return out;
};