Autocomplete.js建议？

I have an autocomplete plug-in (DevBridge AutoComplete) on my text box.

$('#myTextBox').autocomplete({
    serviceUrl: '/Handler/Autocomplete.ashx?'
});

It is making the Ajax call (I can see the JSON return in Fiddler), and I am getting a return like this:

[{"Key":39,"Value":"118"},{"Key":40,"Value":"155"},{"Key":2,"Value":"16"}]

but I keep getting an error:

Unable to get property 'length' of undefined or null reference

On this part of the code:

verifySuggestionsFormat: function (suggestions) {
        // If suggestions is string array, convert them to supported format:
        if (suggestions.length && typeof suggestions[0] === 'string') {
            return $.map(suggestions, function (value) {
                return { value: value, data: null };
            });
        }

        return suggestions;
    }

I'm not sure what this means. Can someone tell me how to fix this? Is it just syntax? I'm not sure where/how to add these suggestions...

suggestions is null or undefined.

Before inspecting the variable, test that it exists:

if (!suggestions) return;

For example:

verifySuggestionsFormat: function (suggestions) {

    // Fail fast if suggestions is not valid
    if (!suggestions) return;

    // If suggestions is string array, convert them to supported format:
    if (suggestions.length && typeof suggestions[0] === 'string') {
        return $.map(suggestions, function (value) {
            return { value: value, data: null };
        });
    }

    return suggestions;
}