Uncaught Error: Weight must be >= 0 (got 0)

[obsidianart]

0 is >=0, this error is unclear.
I think 0 should be an acceptable value.
I'm creating a list and then increment the weight based on parameters, so the original value is 0.

[obsidianart]

var quoteWeights = [
['cold',0],
['warm',0],
['wind',0],
['rain',0],
['littleRain',0]
];
var wq = new WeightedList(quoteWeights);