Unexpected NaN Values When Sorting an Array of Objects with Optional Numeric Properties in TypeScript
I'm currently developing a TypeScript application and I'm running into a frustrating scenario while trying to sort an array of objects that have optional numeric properties. My objects look something like this: ```typescript interface Item { id: number; value?: number; } const items: Item[] = [ { id: 1, value: 10 }, { id: 2 }, { id: 3, value: 5 }, { id: 4, value: undefined }, { id: 5, value: 20 } ]; ``` I want to sort these items by the `value` property in ascending order, but when I try to use the `sort` method, it doesn't handle the optional nature of `value` correctly. Here’s what I’ve tried: ```typescript items.sort((a, b) => { return (a.value || 0) - (b.value || 0); }); ``` This leads to unexpected sorting results, especially when `value` is `undefined`. After running this code, I noticed that the sort order appears inconsistent, and some of the items seem to be placed out of order. I even added logging to see the intermediate values: ```typescript items.sort((a, b) => { console.log(`Comparing ${a.value} and ${b.value}`); return (a.value || 0) - (b.value || 0); }); ``` The output shows that when both values are `undefined`, it doesn't sort them as I expected. It seems like the default comparison when both are `0` doesn't work as intended. In addition, I tried checking for `NaN` values before performing the subtraction: ```typescript items.sort((a, b) => { const aValue = a.value !== undefined ? a.value : Infinity; const bValue = b.value !== undefined ? b.value : Infinity; return aValue - bValue; }); ``` However, this also leads to the first two items being sorted incorrectly. I really want to ensure that items without a `value` go to the end of the list. How can I properly sort this array while handling the optional `value` property correctly in TypeScript? Any insights or best practices would be greatly appreciated!