js pass additional argument to function

Question

I have the following code:

    var createThumb128 = function(fileObj, readStream, writeStream) {
        gm(readStream, fileObj.name()).resize('128', '128').stream().pipe(writeStream);
    };

    var store = new FS.Store.GridFS("thumbs_128", { transformWrite: createThumb128})

How can I replace the hardcoded 128 size strings with arguments that I pass to the createThumb function?

I assume that I cannot just add the additional parameter since the transformWrite property requires a function with the specific 3 parameter signature.

Answer 1

You can try "Currying" https://en.wikipedia.org/wiki/Currying

var createThumb = function(size) {
    return function(fileObj, readStream, writeStream) {
        gm(readStream, fileObj.name()).resize(size, size).stream().pipe(writeStream);
    };
}

var store = new FS.Store.GridFS("thumbs_128", { transformWrite: createThumb('128')})