* @param {Object} input - The object to investigate
 * @returns Object - The specified value if non-null, otherwise an empty array
 * @example {{ readField('jvm', 'files') | nullToEmpty }}
 */
function nullToEmpty(input) {
    let output;
    if (input) {
        output = input;
    } else {
        output = [];
    }
    console.log("nullToEmpty: " + output);

 * @example {{ owners | categorize(branch.diff.files_metadata) }}
 */

function categorize(fileOwners, fileMetadatas) {
    const result = new Map();
    [...fileOwners.keys()].forEach(platform => {
        result.set(platform, {
            name: platform,
            files: []
        });
    });

    Object.values(fileMetadatas).forEach(fileMetadata => {
        [...fileOwners.keys()].forEach(platform => {

/**
 * @module byPlatform
 * @description Groups the PR's files by platform based on the file's path.
 * @param {string[]} files - the gitStream's files context variable
 * @returns {Map} - Map from platform to list of files in this PR in it
 * @example {{ owners | byPlatform }}
 */
function byPlatform(files) {
    const result = new Map();
    files.forEach(file => {
        const platform = getPlatform(file);
        if (!result.has(platform)) {

 * @description Groups the PR's files' by owner based on the CODEOWNERs file.
 * @param {string[]} files - the gitStream's files context variable
 * @param {Object} pr - the gitStream's pr context variable
 * @param {string} token - access token with repo:read scope, used to read the CODEOWNERS file
 * @param {string} pathToCodeOwners - path from repo root to CODEOWNERS file
 * @returns {Map} - Map from owner name to list of files they own

 * @param {String} objectName - The name of the particular object to find
 * @param {String} fieldName - The name of the field for the group to return
 * @returns String - The specified value
 * @example {{ files | byPlatform | categorize(branch.diff.files_metadata) | readField('jvm', 'name') }}
 */

function readField(objects, objectName, fieldName) {
    let group = Object.values(objects).find(s => s.name === objectName);
    if (group) {

        // which re-fixes #24, #38

        // > If there is a separator at the end of the pattern then the pattern
        // > will only match directories, otherwise the pattern can match both
        // > files and directories.

        // 'js*' will not match 'a.js'
        // 'js/' will not match 'a.js'
        // 'js' will match 'a.js' and 'a.js/'
        match => /\/$/.test(match)

 */
function computeStatistics(groupedFiles, fileMetadatas) {
    let totalAdditions = 0;
    let totalDeletions = 0
    let totalChangedFiles = 0;

    let summaries = [...groupedFiles.values()];
    Object.values(summaries).forEach(summary => {
        summary.additions = 0;
        summary.deletions = 0;

        summary.files.forEach(file => {

 * @returns {String} Returns the formatted HTMl table string.
 * @example {{ owners | categorize(branch.diff.files_metadata) | computeStatistics(branch.diff.files_metadata) | summaryTable('Platform') }}
 */
function summaryTable(statistics, title) {
    let preppedStatistics = statistics.filter(s => s.files.length > 0)
        .sort(s => -(s.additions + s.deletions));

const enabled = new Map();

// Require Opt-In/User Request/Community PR
enabled.set('includes_todos', ['community', 'tresat']);
enabled.set('javadoc_on_new_files', ['community', 'tresat']);
enabled.set('lacks_tests', ['community', 'tresat']);
enabled.set('summary_table_owners', ['tresat']);
enabled.set('summary_table_platforms', ['community', 'tresat']);

// Require Opt-In/User Request
enabled.set('code_experts', []);

// Always run