Remove local branches that do not have remote tracking branches.

remove-branches-with-no-remote-trakcing.js

var exec = require('child_process').exec;

exec('git branch -l', function (error, stdout, stderr) {  // retrieve local branches
    var branchesWithoutTrack = [];
    var localBranches = stdout.split('\n')
        .map(function (branchName) {
            return branchName.trim();
        })
        .filter(function (branchName) {
            return branchName.length > 0;
        });
    exec('git branch -r', function (error, stdout, stderr) { // retrieve remote branches
        var remoteBranches = stdout.split('\n')
            .map(function (branchName) {
                return branchName.trim().substring(7);
            })
            .filter(function (branchName) {
                return branchName.length > 0;
            });
        localBranches.forEach(function (localBranch) {
            if (remoteBranches.indexOf(localBranch) < 0) {
                branchesWithoutTrack.push(localBranch);
            }
        });

        if (branchesWithoutTrack.length > 0) {
            exec('git branch -d ' + branchesWithoutTrack.join(' '), function (err, stdout, stderr) {
                if (error) {
                    console.error(`exec error: ${error}`);
                    return;
                }
                console.log(`stdout: ${stdout}`);
                console.log(`stderr: ${stderr}`);
            });
        }
    });
});