Minimalistic javascript assert with stacktrace.

gistfile1.txt

if(!window.assert) {
    window.assert = function() {
        if(!arguments.length || arguments < 2) {
            alert('Invalid assert, use assert(expression, message1, message2, ...)')
            return
        }
        var expression = arguments[0]
        if(!expression) {
            var message = ''
            for(i = 1; i < arguments.length; i++) message += ' ' + arguments[i]

            var error = new Error('Assert failed:' + message)

            console.error(error)
            console.error(error.stack)

            throw error
        }
    }
}