Usage

Guarantees to return a map {}

Arguments are placed in to the map where simple values are used as keys.

The idea is that you might want to let callers optionally provide an alias to a thing, but be concise if they want the default, so:

// okay, you want me to give thing an alias
myLibrary({ 'thing': 'alias' });

// don't use an alias, so ensureMap('thing') produces { 'thing': 'thing' }
myLibrary('thing');

// your code can just assume there will be be a map
function myLibrary(options) {
    var map = ensureMap(options);
    
    // map.thing would be 'alias' for the first myLibrary call
    // map.thing would be 'thing' the second
}

It might make sense to only use it on a sub-property:

function myLibrary(options) {
   var map = ensureMap(options.filesToProcess);
}