in miredot/lib/lunr/js/lunr.js [441:450]
lunr.Pipeline.prototype.before = function (existingFn, newFn) {
lunr.Pipeline.warnIfFunctionNotRegistered(newFn)
var pos = this._stack.indexOf(existingFn)
if (pos == -1) {
throw new Error('Cannot find existingFn')
}
this._stack.splice(pos, 0, newFn)
}