grunt-browserify Path must be a string error

Question

I'm trying to run grunt-browserify. I keep getting the "path must be a string" error.

Here's my browserify task:

browserify: {
    dist: {
        files: {
            "build/Hotspot.js" : ["lib/**/*.js"]
        },
        options: {
            transform: ["babelify", {
                presets: "es2015"
            }]
        }
    }
},

This returns a Path must be a string error. However, if I change files to

"build/Hotspot.js" : ["/lib/**/*.js"]

the task runs, but none of the code seems to be transpiled or bundled. build/Hotspot.js is just the standard browserify error handling and nothing else.

Is there something I've done wrong in setting up my Gruntfile?

edit 1: I should note that lib/ exists and has files in it. Also, "./lib/**/*.js" yields the same error.

Answer 1

I think the clue to the solution is in the grunt-browserify docs, specifically:

Transforms can also be provided with an options hash; in this case, the transform should be specified as an array of [transformStringOrFn, optionsHash].

I think this is telling us that in order to pass the options hash to a transform, the options.tranform value must be an array of arrays:

transform: [
    ["babelify", { presets: "es2015" }]
]